Telkom error -2 months and still awaiting credit

I logged a case on the 13 January 2018 (081 180) relating to an additional R300 charged for device obligation/carryover .The call centre had confirmed that the amount was charged in error and that she would log the error which should be resolved with 72 hours and I could expect my credit on my next statement .Today I received my statement and to my surprise there was no credit. I called the number again and the agent (Hlengiwe ) advised that the system showed the case was still open which means it wasn't attended to .This is ridiculous that Telkom makes a mistake and I have to wait for almost 2 months for my credit. I have budgeted only for the amount less than R300 and Telkom will have to amend my statement accordingly .