This is why you need a staging server and test cases. You only upgrade in the weekends after fully testing. Also, you always need to be extra careful with paym

This is why you need a staging server and test cases. You only upgrade in the weekends after fully testing. Also, you always need to be extra careful with payment code. We test it multiple times before deploying it. Granted all this wouldn't had helped OP, still you need to test everything before upgrading and deploying.