Dont open an Mtn contract

I had extra cash in december and decided to pay into my account , mtn magtape ran and the debit order ran as well , no problem with that. I called them and they said the debit order will still run even though my account was in a credit. I thought to myself there was no point making the r2000 cash payment , i requested a refund of the r2000, they told me only r1400 was sitting in credit because the invoice ran, i asked them to refund the r1400 , to date i am still calling them for the refund and they making me cry for my money. Sad how a loyal customer gets treated this badly. I have a contract for more than 10 years.