MTN takes airtime and keep removing record thereof

On the 14th of February I was working at an event in Cape Town and had so many issues with the network. I could only make 1 phone call at a time and then it said that my airtime has be n exhausted. I put about R180 worth of airtime and data on my phone that day and made approximy 10min worth of calls. I eventually stopped loading airtime as it kept dissapearing. The next morning I tried again and data dissapeared again. Later that day I loaded data again and all was fine and has been since. I logged 3 calls with the call centre and heard nothing back. I thought I would call back again today and all records have been removed on the call centre side. I overheard someone telling their friend that MTN has been *****ing her airtime and I reconed the same thing has happened to me. I demand I get refunded asap. I hav given MTN more than enough time. Obviously I am not the only one who has experienced this problem. I expect an answer within 24 hours.