thread Re: OpenCart Coupons results in cancelled orders in Payments Troubleshooting

OpenCart Coupons results in cancelled orders

dartpro — Sun, 21 Sep 2025 13:29:48 GMT

Using Square to receive payment. All ok.

However to increase sales, we are offering discount coupons. This is where the problem starts.

If a customer uses a coupon, they get a square error that there was a problem, however the customer card still get charged.

Its seems there is a mismatch somewhere between the discounted total amount and original total amount, which makes the transaction fail, after payment has been made.

Similarly, if the customer uses a store creditcredit, voucher or anything that will provide a discount, the failure happens.

Does anyone know how to go about fixing this? Or where i should be looking. What is the process Square follow end to end to receive payment?

Re: OpenCart Coupons results in cancelled orders

dartpro — Tue, 30 Jun 2020 07:55:03 GMT

I understand the problem may be linked to payment gateways that use a callback to confirm the order. Does anyone know if Square uses a callback ?

Re: OpenCart Coupons results in cancelled orders

tranguyen — Tue, 30 Jun 2020 10:00:10 GMT

Hi @dartpro, so sorry to hear you are having this issue! Was the coupon code created from OpenCart, or was it create via Square?

If you have a screenshot of the error message, that'll definitely help me look into this as well!

Re: OpenCart Coupons results in cancelled orders

dartpro — Tue, 30 Jun 2020 11:16:01 GMT

@tranguyen Thank you for replying.

The coupon was created in OpenCart to give a 10% discount.

When the customer purchases, and apply the code, it gives the correct discount.

The customer then goes ahead to make payment.

Square Process the payment successfully and instead of returning a success message, it returns an error. and the order gets instantly canceled. The payment shows on the SQUARE dashboard is successful.

The exact error message displayed to the customer is:
Unexpected website error. Please contact the store owner on +44 1234567 or e-mail admin@myemail.com. Note that your transaction may be processed."

Have combed the whole of the internet, the likely reason why this is happening is that there is a mismatch during one of the background checks.... The discount price is lower than the expected price and triggers an error or anti-fraud block, i.e. payment gateway using a callback to confirm the order.

Any help will be appreciated.

Re: OpenCart Coupons results in cancelled orders

tranguyen — Wed, 01 Jul 2020 10:25:29 GMT

Thanks for sending that on, @dartpro! It does sound like the error is caused by a discrepancy between Square and OpenCart.

I think it might be best if you can reach out to our Support team directly with example of specific transactions - our team will be able to check what the error message we are seeing on those transactions and troubleshoot what might be the issue here.

Here are the steps to contact Square Support by phone or by email:

Go to https://squareup.com/help/gb/en/contact
Select your topic or just click Other > I don’t see my issue, it’ll give you the option to either call or email in!

The phone number for Square Support is 0800 098 8008. The Square Support Team is available by phone Monday to Friday, 9am to 5pm.