Repairs done but tab still have the same problem

I took in my Galaxy tab in for repairs. It has a softwaer problem. The tab was sent away and when I recieved it back I loaded my apps again, then the same problem accourd. After opening some apps the tab switches off and back on. I tookit back again and was without my tab again for more than a week. I recieved my tab back and asked the shop assistent what was done on repairs, she could not tell me what was done. I loaded one app while at the shop. When i opend the app, same problem, the tab switched off and on. I was told that i can book it in again. Apparently after 5 times at the repair shop the manufacturer will be notified about the problem I am without my tab for half of the month and every time I reload apps on the tab it cost me money on data. I feel like canseling my contracts with Vodacom and move over to a other network. Very unhappy about the level of service