gistfile1.txt

        public bool ValidateExpiryDate(string cardExpiryDate, DateTime lastPaymentDate)
        {
            if (cardExpiryDate == null || !CardDateUtil.FormatIsValid(cardExpiryDate)) return false;

            DateTime expiryDate = CardDateUtil.ConvertToDateTime(cardExpiryDate, SetDayOfMonth.LastDayOfMonth);

            var invalidExpiryDate = lastPaymentDate.AddMonths(3); //TODO: pass as variable

            var inDate = expiryDate >= invalidExpiryDate;

            return inDate;
        }