Tablet went for repairs but not fixed

I lodged a complaint with Mtn about a tablet that went dead at the begging of June. A month later it was collected and it went for repairs. I was given a loan tablet that but it was not such of a help cause my son was unable to load his text books from school. On the 11 Aug the tablet came back but when i got home it was not working still. I sent an email to Mtn on the 13 Aug 2015 but i still haven't heard anything from them. I find this really disturbing cause i pay my instalments every month already in 6 months this is the kind of service i got.