MTN worst Service Provide

I have a router data contact with MTN. My frustration started during isolation when I want to get hold of MTN but could not manage to speak to someone. My data run out and I want to check what was going on. I went to the MTN store Tygervalley on 3 July 2021 DUE TO THE FACT THAT MY DATA was depleted (in an email from customer care I got other information - not that data was depleted). So I bought data for R500. Next thing on 1 August MTN took +/-R4 700 from my account. With my visit to the store on 1 August they told me it is due to my limit which is set at R5 000. Why would I have a limit of R5 000 and who set it. Previous month my usage was block due to depletion of data. I NEVER ASKED OR INSTRUCTED MTN to add a limit of R5 000. I've asked for the 'fingerprint' of how set the limit. They just don't answer my questions. It is the most difficult compony to deal with if you has a problem. Phone 135 with the menu you just go in circles Never able to speak to someone. In the store the just tell you contact Customer Service as they cannot track the 'finger print' of who changed the limit. None of my questions was answered in my email request.