bad mtn service

Recently from actually beginning of the year mtn has given us nothing but very very bad service and unexplained disappearing of airtime and data . apparently they send A million smses and this other message of wow bonus where ur airtime will disappear and you get 100 min mtn-mtn n 20 MB that will restrict u to make calls or smses to other network,apparently even the customer care can't explain this nonsense will give u many code to dial but can't explain where ur airtime has gone to,i mean why would they wanna restrict u from calling networks of ur choice with ur own money.am really frustrated but this because it happens all the time and seems as if we are being ****** or we are actually covering their debts am now so much tired of calling unskilled customer care people and repeating myself all over because it show that am not subscribed to anything so where the hell does the airtime go?