private async void Claim_Clicked(object sender, EventArgs e)
{
var voucher = FindViewById <Spinner>(Resource.Id.spnVoucher).SelectedItem;
var id = GetVoucherId(voucher.ToString());
var claimResponse = await _voucherService.ClaimVoucher(id);
Toast.MakeText(this, $"{claimResponse.Error.First()}", ToastLength.Long).Show();
}
