Unable to repair phone

My phone started to reset itself . The phone , a Samsung S3 Mini is under contract guarantee. It was send into the Vodacom repair shop . After i received it back the same thing happend. After the 3rd time it was send in the problem still presist . <br> The Vodacom shop (Cell Shack Groblersdal) were my contract is are just as fed-up with the quality of repair which they get from Vodacom . <br> Im not complaining about Cell Shack but against Vodacom Repair in Witbank. <br> Cell Shack also told Vodacom that the phone is under guarantee and should be replaced. Every time the phone is send to Witbank it takes about three weeks to come back .<br> Please help me and all the other cell phone users in groblerdal en Witbank