Samsung S6 Edge signal problem/overheating/battery

Upgraded through Vodacom to Samsung S6 Edge at begining of September 2015, during which period phone has never connected to Vodacom's LTE network. After a month battery started draining within 5 to 6 hours and phone heated up that metal casing burns your hand. Took phone to Samsung Clearwater Mall twice - both times a hard reset was performed, but phone acted in same way. Book phone in at Vodacom Cresta more than 2 weeks ago just to hear whole motherboard and screen had to be replaced. For over a week the phone has been with Vodacom as \Samsung's IMEI writer does not work"and phone's IMEI number can not be overwritten... So much for Samsung's \""flagship\"" phone"