Unprofessional service from a law firm

First of all, this people will harass you with calls & sms. MBD is debt collector for vodacom, after few weeks of their hostile treatment I settled my accout on the 3rd July 2020. They promised to send me proof of payment/settlement letter. It has been a week now. When you can they offices, the consultants just lie to be that they have escalated the matter to their supervisor. Everytime you can, I talk to a different person.