Greedy MTN does it again

I had an account with MTN which I decided to close as I felt that MTN was robbing me especially with their data which does not last as long as other networks, namely telkom mobile. I also have a vodacom contract which is also far much better than MTN.

I paid the settlement amount which I was asked to pay by the detentions department. I paid the amount using credit card on the MTN website. I then later discovered that after closing the account, MTN actually now owed something like 370rands meaning I had been overcharged by them. I tried to request for the refund and never got any feedback. After complaining on hellopeter I got this funny but sad response, "Kindly note that banking rejected the previous request as they require the proof of payment to be attached. Please send the proof of payment for the final payment that you made in order for the refund to be processed to ********** How am i going to get proof of payment when I did a credit card payment on their own (MTN) website? In any case you don't need to be a rocket scientist to know that on my account number there are funds lying there and there is no contract that is active. Where does MTN think the funds came from? From the sky? This is utter nonsense that is not expected from a company as big as MTN. Yes from a burial society that can happen but not from a big company. But then MTN has proven to be a greedy company in recent days which is why I cancelled my contract with them in the first place. Its no surprise that their banking department would demand proof of payment when they have the records right there with them, unless they are too uneducated to know what is a credit card payment and how to trace the same.