Paying so much for something I cannot use!

Accounts keep getting soft locked month after month because of a credit limit put in place. This limit keeps getting exceeded when current invoice and proposed invoice are added together, for some reason. Anyway, after trying for days now (after having the limit increased) my number is still locked and I have to waste time calling the call centre and waiting up to 15 minutes for them to try figure out what is wrong!!! Rotten service Vodacom.