Shopping Center With Bag - time limits

namespace ShoppingCenterWithBag
{
    using System;
    using System.Text;
    using Wintellect.PowerCollections;

    /// <summary>
    /// Slow for BGCoder - gets 60/100 and time limits the bigger tests.
    /// </summary>
    public class ShoppingCenterWithBag
    {
        private const string ProductAdded = "Product added";

        private const string XProductsDeleted = " products deleted";

        private const string NOProductsFound = "No products found";

        private const string IncorrectCommand = "Incorrect command";

        private static readonly OrderedBag<Product> center = new OrderedBag<Product>();

        public static void Main()
        {
            StringBuilder answer = new StringBuilder();

            int commands = int.Parse(Console.ReadLine());

            for (int i = 1; i <= commands; i++)
            {
                string command = Console.ReadLine();

                string commandResult = ProcessCommand(command);

                answer.AppendLine(commandResult);
            }

            Console.Write(answer);
        }

        public static string ProcessCommand(string command)
        {
            int indexOfFirstSpace = command.IndexOf(' ');

            string method = command.Substring(0, indexOfFirstSpace);

            string parameterValues = command.Substring(indexOfFirstSpace + 1);

            string[] parameters = parameterValues.Split(new char[] { ';' }, StringSplitOptions.RemoveEmptyEntries);

            string commandResult;

            switch (method)
            {
                case "AddProduct":
                    {
                        commandResult = AddProduct(parameters[0], parameters[1], parameters[2]);

                        break;
                    }

                case "DeleteProducts":
                    {
                        if (parameters.Length == 1)
                        {
                            commandResult = DeleteProducts(parameters[0]);
                        }
                        else
                        {
                            commandResult = DeleteProducts(parameters[0], parameters[1]);
                        }

                        break;
                    }

                case "FindProductsByName":
                    {
                        commandResult = FindProductsByName(parameters[0]);

                        break;
                    }

                case "FindProductsByPriceRange":
                    {
                        commandResult = FindProductsByPriceRange(parameters[0], parameters[1]);

                        break;
                    }

                case "FindProductsByProducer":
                    {
                        commandResult = FindProductsByProducer(parameters[0]);

                        break;
                    }

                default:
                    {
                        commandResult = IncorrectCommand;

                        break;
                    }
            }

            return commandResult;
        }

        private static string FindProductsByProducer(string producer)
        {
            int counter = 0;
            var found = center.FindAll(x => x.Producer == producer);

            StringBuilder results = new StringBuilder();
            foreach (var row in found)
            {
                results.Append("{");
                results.AppendFormat("{0};{1};{2:f2}", row.Name, row.Producer, row.Price);
                results.Append("}");
                results.AppendLine();
                counter++;
            }

            if (counter == 0)
            {
                return NOProductsFound;
            }
            else
            {
                results.Length--;
                results.Length--;
                return results.ToString();
            }
        }

        private static string FindProductsByPriceRange(string priceFrom, string priceTo)
        {
            int counter = 0;
            var rows = center.FindAll(x => x.Price >= decimal.Parse(priceFrom) && x.Price <= decimal.Parse(priceTo));

            StringBuilder results = new StringBuilder();
            foreach (var row in rows)
            {
                results.Append("{");
                results.AppendFormat("{0};{1};{2:f2}", row.Name, row.Producer, row.Price);
                results.Append("}");
                results.AppendLine();
                counter++;
            }

            if (counter == 0)
            {
                return NOProductsFound;
            }
            else
            {
                results.Length--;
                results.Length--;
                return results.ToString();
            }
        }

        private static string FindProductsByName(string product)
        {
            int counter = 0;
            var found = center.FindAll(x => x.Name == product);

            StringBuilder results = new StringBuilder();
            foreach (var item in found)
            {
                results.Append("{");
                results.AppendFormat("{0};{1};{2:f2}", item.Name, item.Producer, item.Price);
                results.Append("}");
                results.AppendLine();
                counter++;
            }

            if (counter == 0)
            {
                return NOProductsFound;
            }
            else
            {
                results.Length--;
                results.Length--;
                return results.ToString();
            }
        }

        private static string DeleteProducts(string producer)
        {
            int counter = 0;
            counter = center.RemoveAll(x => x.Producer == producer).Count;

            if (counter == 0)
            {
                return NOProductsFound;
            }
            else
            {
                return counter + XProductsDeleted;
            }
        }

        private static string DeleteProducts(string product, string producer)
        {
            int counter = 0;
            counter = center.RemoveAll(x => x.Producer == producer && x.Name == product ).Count;

            if (counter == 0)
            {
                return NOProductsFound;
            }
            else
            {
                return counter + XProductsDeleted;
            }
        }

        private static string AddProduct(string name, string price, string producer)
        {
            Product product = new Product(name, decimal.Parse(price), producer);
            center.Add(product);

            return ProductAdded;
        }
    }

    public class Product : IComparable<Product>
    {
        public string Name { get; set; }
        public string Producer { get; set; }
        public decimal Price { get; set; }

        public Product(string name, decimal price, string producer )
        {
            this.Name = name;
            this.Producer = producer;
            this.Price = price;
        }

        public int CompareTo(Product other)
        {

            int resultOfCompare = Name.CompareTo(other.Name);

            if (resultOfCompare == 0)
            {

                resultOfCompare = Producer.CompareTo(other.Producer);

            }

            if (resultOfCompare == 0)
            {

                resultOfCompare = Price.CompareTo(other.Price);

            }

            return resultOfCompare;

        }
    }
}