Unbelievably bad service and *********

I went into Telkom branch in Bayside, Table View on the 24/03/2014 !!! to give them notice that I was ending my contract for 8ta data bundle ( I have the proof for the cancellation on paper given to me as receipt that day). They continued to bill me monthly as of that date until the November 2015. After having stopped using the data bundle at the end of March in 2014 after which the sim was disgarded!!! After countless emails and correspondence inside the branch and telephonically with Telkom agents x5 they finally \cancelled\" my account in December 2015 and reimbursed me for 1 MONTHS USAGE AFTER HAVING WRONGFULLY DEBITED MY ACCOUNT FOR 21 MONTHS and having me wait two full months for the supervising person/ manager to leave me a message with my RECEPTIONIST (without a number to call back) saying that the credit owed to me will be shown on my next invoice!!! I mean I don't even have account with them anymore how will I even use this incorrect amount owed to me and why are they sending me an invoice! Hopefully this is not the way Telkom does business otherwise our telecomunication industry and their clients are in deep ****. "