Two month old Samsung S6 overheating when charging

I have my Samsung S6 for two months & it's been overheating when I charge it. My devise has been in twice already to the Vodacom Repair Centre in Canal Walk (22nd Dec'15 & 06th Jan'16), how many more times does my devise have to go in before this problem is solved, surely a two month old brand new phone should NOT be overheating when you charge it. As far as I'm concerned this is a hazardous & clearly this is a faulty devise. I'm extremely unsatisfied with both Vodacom & Samsung in the way that they have dealt with this issue.