Payment allocation

Not happy with the way they handled my fathers case, he made a payment of R33 000 on his vehicle finance account they kept on calling saying that they did not receive the payment and we do have a proof that we paid. what is stressing more is that when we call them to request them to allocate the payment we don't get any Joy we've been talking to 3 different consultants and their response is not the same we have emailed them POP promising to reply if they get the email but still am Just fed up