10G data offer, added incorrectly to contract

I was contacted on Friday 10 July 2015 by call centre (marketing) offering me a 10g data bundle for a once of amount of R640, and according to the call centre operator the bundle does not expire. I asked Brenda the operator to phone me back for an answer. When she phoned back in 30 min, I asked her to add the bundle to my 2nd contract, which she said is 100%. The bundle would have been loaded in 24-48 hours. This only happened in 72 hours and to the wrong contract. I contacted the call centre on Monday to request the removal of the bundle from my contract. Only then they confirmed that this bundle expires after 60 days and not as they explained when selling it to me. Since Monday I have't had any feedback on the call logged and the bundle has not been removed. I am not willing to pay for a data bundle I don't need on the contract. I find MTN SERVICE APPAULING!!!!