Useless and incompotent staff

I had numerous issues with Telkom during the months of Aug, Sept and October with regards to my internet, I received an SMS afterwards confirming my total credit for the amount of R2250, which is 3 months premiums, in November and December I received an invoice indicating there is 0.00 outstanding on my account, in January I received an account for the amount of R750, which I paid as disputing anything with Telkom takes way too long. This month, after recieving no account at all, I contacted Telkom to dispute my credited amount, I spoke to a lady who escalated my query, today on the 8th of March, I spoke to a lady named Yoliswa from the Dispute Resoltution department, she was as useless as a ****** with a dictionary, the more I explain myself, the less interested she seemed, after numerous attempts at requesting details to speak to someone who will be able to tell me where the credit info on the SMS came from, she can only say she does not know, this lady knows less than Jon Snow. I obtained her manager's number but that also just rings, as expected from any Telkom assistance.