MTN!!!!

So yesterday I still get a ye text message from MTN saying I owe them R800 this people I spoke to them regarding my contract I called in spoke to a guy agent asked him when is my last payment he said the end of May I say okay cool. END of May they debited so now how am I owing MTN so much money one of their supervisors said they will listen to that call and give me feedback she never called back MTN you guys are ****mers