There is a business rule for which, if the customer’s credit card is declined because there are no sufficient funds, the system tries to force the payments 3 times, at the third time it will automatically apply a 50% discount on the payment.
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For normal orders, these attempts are done the same day the customer place places the order, for 15 days day free trial these attempts are applied within 5 days between each other, once the system triggered the charge at the end of the trial.
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In other words, if the customer’s pre-paid card is declined because of insufficient funds, then at on the third attempt the customer is not going to receive the 50% discount as before.
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