public async void OnExecute(object sender, EventArgs args)
        {
            if (payment != null)
            {
                payment.CardInfo.ExpiryMonth = ReturnNumeric(ExpiryMonth);
                payment.CardInfo.ExpiryYear  = ReturnNumeric(ExpiryYear);
                payment.CardInfo.Cvc         = ReturnNumeric(CVV);
                await payment.UpdateAsync();
            }
            else
            {
                var card = new Card
                {
                    Number      = CardNumber.Text,
                    ExpiryMonth = ReturnNumeric(ExpiryMonth),
                    ExpiryYear  = ReturnNumeric(ExpiryYear),
                    Cvc         = ReturnNumeric(CVV)
                };
                payment = await PaymentModel.AddAsync(card).ConfigureAwait(false);
            }

            if (!payment.isRequestSuccessful)
            {
                Device.BeginInvokeOnMainThread(() =>
                {
                    DependencyService.Get <IMessage>().ShortAlert("Failed to add your card");
                });
            }
            else
            {
                Device.BeginInvokeOnMainThread(() =>
                {
                    DependencyService.Get <IMessage>().ShortAlert("Successful!");
                    DataSender(sender, new FormEvent()
                    {
                        Object = payment
                    });
                });
            }
        }