Brand new Phone that never has signal

I upgraded in April on my contract to a Samsung Galaxy S6 Edge. Ever since I got the phone I had signal problems with it. First it just didn't receive calls or messages for days on end until I call the call centre and then I magically works. Now my phone only has signal in one spot in our house and random areas if I go to the shops. I have NEVER had a problem with signal ever where we live or anywhere else for that matter. But for the past 2 months this phone just does not receive calls. The phone just cuts out. It's only 6 months old?????? And the other thing is that the battery literally only lasts an hour even if I don't play on my phone at all. And the phone gets so extremely hot that I cannot touch it. The phone could be lying on my bedside table all night and when I pick it up in the morning it's so hot I cannot touch it. This is a massive problem. But I've been to your store in Clearwater and they told me to sort it out with Samsung and when I went to Samsung I was told to sort it out with Vodacom???? I now want answers as to what can and will be done about this phone? I have a 2 month old baby and cannot afford to have an expensive cellphone that simply does not work!!!??