Lack of service from account department

I am utterly appalled by the lack of service MTN is providing. My account has been sent to legal as according to them my account has not been paid. I have sent proof of payment many of times. Payment was made on the 28/09/2023 and still it has not been 'found'on the system. How long does it take to allocate a payment or to find one? Does the accounts department not want to work?