Mtn t h e f t of pre paid airtime

I hve been watching my balance in airtime like a hawk the last 3 days. 160 dwindled down to 43.00 with me only making 2 ph calls 3sms and still having a data balance of over 400Mb. Explain that away MTN. Not only are you the worst service provider in Africa with constant issues with lost signals and data etc supply problems to yr clients now this. Resorting to unauthorised and automatic deductions fm yr client's prepaid airtime. To add insult to injury there is yr constant unwanted barrage of promotional sms's coming through to my ph. 1st and last time I have a contract with MTN