Bad service

I had an account with Nashua Vodacom that was handed over to VVM, I managed to settle my account in October but I am yet to receive my paid up letter. Been contacting them several times being promised that the paid up letter will be sent through like I was promised when I settled the account but still have not received anything from them. They hustle you with calls, text message to pay your but when you do you become forgotten. Truly disappointed in their service