Nedbank paid-up letter delay

Please help me resolve my issue with Nedbank. I settled my loan last year March 2020, I've recently found out that Nedbank handed my account over to a debt collection agency for the amount of R280.00 which is ridiculous. I resolved the situation only to find out I've been handed over to DMC another agency...frustrating since the account is settled. I have comorbidities and refuse to spend time in a stuffy bank. Any advice on how to get my paid up letter? ***