No data for 8 months

I am currently on a 2GB data plan , however for the past 8 months , the SIM card has ceased to function at all. Despite numerous attempts and enquiries at various mtn stores ( esp Campus Square, Johannesburg), no fault was found. However, the subscription continued to be debited from my account. Eventually, I presented this problem to the mtn store in Clearwater Mall, and much to my relief they were able to restore the sims function. Apparently the sim had been barred with no explanation what so ever, and all the data that was essentially paid for, lost /******. Unacceptable service and customer care.