Qt tableview

mainwindow.cpp

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    QStandardItemModel *model = new QStandardItemModel(0,5,this); //2 Rows and 3 Columns
    model->setHorizontalHeaderItem(0, new QStandardItem(QString("Company Name")));
    model->setHorizontalHeaderItem(1, new QStandardItem(QString("Phone")));
    model->setHorizontalHeaderItem(2, new QStandardItem(QString("Email")));
    model->setHorizontalHeaderItem(3, new QStandardItem(QString("Contact person")));
    model->setHorizontalHeaderItem(4, new QStandardItem(QString("Phone")));

    //tablemodel
    this->tablemodel = model;
    ui->tableView->setModel(model);
}

//accesor method for the table model
QStandardItemModel* MainWindow::tm(){
    return this->tablemodel;
}

clientInfo.cpp

void ClientInfo::on_buttonBox_accepted()
{

    //get the user data

    //company details
    string companyName = ui->companyName->text().toStdString();
    string companyPhone = ui->companyPhone->text().toStdString();

    //now disply this to the table
    MainWindow *mw = new MainWindow();

//get the model using accessor method from the main window widget
    QStandardItemModel *model = mw->tm();
//fill in the data
    model->setItem(0,0,new QStandardItem(QString(companyName)));
model->setItem(0,1,new QStandardItem(QString(companyPhone)));

//when i click okay, this data is never reflected on the main window!!
//what am i missing?

}