Phone not repaired

In July 2015 I upgraded my cellphone contract and opt for the Samsung Galaxy S6 Edge smartphone. Within a week I had to take it back and fight to get it exchanged. Now less than 7 months it had to go in for repair again. The phone has no data connection and is getting so hot that you can't even hold it in your hand not to mention holding it against your ear when talking on it. Got the phone back today...repair report \no fault found on device\". Switched it on and the same problem is still there. I still have no data connection and the normal signal reception is now even worse. Before I had LTE reception in and around my house and workplace and now only edge if I'm lucky, but there is nothing wrong with the piece of ****. Sadly I upgraded my second contract already and now still waiting for the delivery. Maybe I should cancel that upgrade and get Sony"