Refusing to acknowledge payment

I made 2 online payments to Ackermans during lockdown. One in April and one in May. I sent through proof of payment which I received from the bank multiple times, but they are refusing to take the amount of my account. According to them, the proof of payment must be in a certain format. I lost track of how many different people I spoke to at the Call center, and it has still not been sorted out. I've had it with Ackermans.