Tuckshop of a business

I've had the worst experience with Meter Shack. Firstly, out of the blue my balance was sitting at -R3559 after I had bought electricity the previous week. I tell them and they say they have reversed the charges because it was not my fault, obviously. A couple of days later I recharge again on a Friday, I'm not home the entire weekend and then on Monday my account is on -R579. No one responds on their whatsapp. I don't know what kind of tuckshop these people are running but not with my money.