Airtime theft

I have multiple times tried to report the issue of disappearing airtime, each time tell send me a code to cancel subscriptions I never subscribed to. so each time I need to cancel subscriptions that I am unaware of, and they seem to be no subscriptions but airtime still disappears. At that point were I stay I need to buzz each time I'm stepping out or coming in that means I need to recharge twice or more a day.