private Tuple<bool, string> isPaymentValid(titizOto.Models.titizOtoEntities db)
        {
            switch (this.paymentOptionChoose)
            {
                case paymentOption.noAnswer:
                    return new Tuple<bool, string>(false, null);

                case paymentOption.transfer:

                    if (this.transferInfo != null)
                    {
                        var eftItem = db.tbl_bankEft.Where(a => a.bankEftId == this.transferInfo.selectedTransferId).FirstOrDefault();

                        if (eftItem != null)
                        {
                            return new Tuple<bool, string>(true, null);
                        }
                    }

                    return new Tuple<bool, string>(false, null);

                case paymentOption.creditCard:

                    if (this.cardInfo != null)
                    {
                        checkoutShared cs = new checkoutShared(db);
                        var cardInfoValidation = cs.isCardInfoValid(this.cardInfo);
                        return cardInfoValidation;
                    }

                    break;

            }

            return new Tuple<bool, string>(false, null);
        }