"[
     {"created":1487173664,"email":"lklklk@kkk.com","reason":"550 No Such User Here ","status":"550"}
    ,{"created":1487169530,"email":"bb@hotmail.com","reason":"550 Requested action not taken: mailbox unavailable ","status":"550"}
    ,{"created":1487095343,"email":"lsdkjf@hotmail.com","reason":"550 Requested action not taken: mailbox unavailable ","status":"550"}
    ,{"created":1487093087,"email":"sldf@hotmail.com","reason":"550 Requested action not taken: mailbox unavailable ","status":"550"}
    ,{"created":1487085008,"email":"sdlkfj@hotmail.com","reason":"550 Requested action not taken: mailbox unavailable ","status":"550"}
    ,{"created":1487082934,"email":"mickey.mouse@disney.com","reason":"550 Invalid recipient <mickey.mouse@disney.com> (#5.1.1) ","status":"550"}
]"

[DataContract(Name = "SendGridBounce")]
public class SendGridBounce
{
    [DataMember]
    public int Created { get; set; }
    [DataMember]
    public string Email { get; set; }
    [DataMember]
    public string Reason { get; set; }
    [DataMember]
    public string Status { get; set; }
}

[CollectionDataContract(Name = "SendGridBounceList")]
public class SendGridBounceList : List<SendGridBounce>
{
}

var client = new SendGridClient("some API key here");
string queryParams = String.Format(CultureInfo.InvariantCulture, "{{ 'end_time': {0},  'start_time': 1 }}", DateTimeOffset.UtcNow.ToUnixTimeSeconds());
var response = Task.Run(() => client.RequestAsync(SendGridClient.Method.GET, urlPath: "suppression/bounces", queryParams: queryParams)).Result;

DataContractJsonSerializer js = new DataContractJsonSerializer(typeof(SendGridBounceList));
using (MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(response.Body.ReadAsStringAsync().Result)))
{
    SendGridBounceList bl = js.ReadObject(ms) as SendGridBounceList;

    foreach (var b in bl)
    {
        tbxOutput.Text += b.Created.ToString() + ", " + b.Status + ", " + b.Email + ", " + b.Reason + Environment.NewLine;
    }
}