MTN Ermelo Poor Client service!!!

This store has very poor service. I have logged a complaint with Elize (don't know whether she is the manager or owner). This complaint was logged in person with Elize at the beginning of February 2018. Up until today Elize has not been able to resolve this problem for me. Everytime that I phone to follow up, she gets more and more irritated and she actually tells me that I must rather phone MTN myself because she is very busy and does not have time to resolve my query. She gave me a reference number and I tried to phone MTN myself, but they just transfer me from one *********** soul to the other and nobody can help me. I was overcharged by almost R3000 at the end of January 2018 and I would like to have a refund. I was on a top-up package and according to Elize her system also shows that I was on top-up. Now MTN tells me that I must proof to them that I was on top-up. How on earth do I do that? According to them Elize must find the original paper that I signed in 2014. I told this to Elize, but she says that she can't find anything and therefore she suspects that I did my upgrade elsewhere. I told her very firmly that I did the upgrade at her shop and then she hung up. Haven't been able to get hold of her since. Very rude and unprofessional. I will never set foot in her shop again and I will transfer my contract to a different service provider. MTN SUCKS!!!!!!!!!!!!!!!!!! ESPECIALLY MTN ERMELO (57 Kerk Street, next to Wildman)