Vodacom - Disgusted

I have made a payment earlier this year which was allocated as a invoice instead of a credit - Why....that only Vodacom can confirm. Ever since, they have been bombarding me with calls and emails to advise me that I owe them this one month instalment, I have been on calls with their agents trying to resolve this issue for over 5 months now. The last agent confirmed that they will change this invoice to a payment, this was clearly also not done. I had to remove my Vodacom simcard from my dual phone to save myself from this non stop harassment, only realising afterwards that my business is linked to this number and that some of my clients do not have my alternative contact number. As of a few days ago, the automated calls started again after inserting the sim.

How is this possible for such a massive company not to resolve minor issues like this.

Believe you me, I'm convinced that I am not the only once that will not be re-newing a contract when dew.