how safe are your Samsung devices

On the 08/04/2016 my Samsung A5 phone was on charge (1 year and 1 month old), while it was on charge the phone overheated it melted the charger,melted the back of the phone n even burnt my bedsheet (as in the picture) when seeing my phone like this I was shocked as this could have turned out much worst with my 4 year old sleeping next to where the phone was on charge. The very next day I had taken my phone to Samsung smart care centre in Constantia business Park on 14th Avenue where I was told they will contact me within 7-14 days. its going for almost a month now and I have not been contacted once. I was cool with it at first but this now is driving me insane as when I was there and enquired if they could rent me a phone they told me straight no. Now im sitting using an old phone which I can barley do much with it where as I have a smart phone which Im still paying for on contract every month sitting somewhere at Samsung. In my opinion I still think the old phones where the batteries were removable were much more safer than this new style built in batteries.