Airtime disappear prom my sim

Every time i put airtime on my top up phone is disappear from my phone. This is the 3rd time this happen over a period of a year. When i calk sell C al they can say id that it is automatic updates. And they lying. My auto updates are off. It is not on. They steel my airtime and my data. And lying about it. Telling me that 10.54 i was on the internet. Its a lie; my phone was in my handbag in tge cupboard at work. When its working hours im not allow on my phone.