SERVICE TIME UNACCEPTABLE

I've send my Samsung tablet in for repairs as it switches off while you busy using it. MTN let me sign a document that I will have to pay R350 if they take a look at it and don't accept the quote. My question is why is it not a warranty claim as the tablet is still under warranty. Then they send me an sms with the total amount it will cost to fix my tablet. No breakdown of explanation of what is wrong. I've accepted the quote via sms and waited. after 2 weeks I've contacted the branch to find out what happened. The branch manager then informed me that I have to pay the money before they will fix the tablet. I've paid the money that same day and now after 3 week are still waiting for my tablet to come back. The branch manager says its the service department striking causing the problem. I just want my tablet and also want to know if MTN is going to compensate me for the inconvenience caused while they go on holiday.