Battery fault on Samsung Galaxy S7

After having my Samsung Galaxy S7 for about 18 months the battery started giving problems. The phone would just shut down after still showing 80% battery power and then when I would switch it on again it would show 0% battery power. I decided to take it to my MTN store in Cresta where it was discovered (after taking it out from it's protective cover) that the battery was swollen and the body shell of the phone and the screen was separated by a huge margin! I was informed to not use the phone anymore as it could explode and that it is a wonder it hasn't exploded already. MTN could not assist from their side but phoned Samsung Head Office while I was there as the phone was still under warranty only to get told that because it is the battery the warranty on it is only 6 months!!!!! And that I can pay to have it fix at about R2000 or more and that that would take about 6 weeks!!!! This is totally unacceptable to me as it clearly is a battery fault and very dangerous for anyone to use. I was even more shocked (after asking advise from various cellphone stores/repair shops) to hear that this happens regularly. Why should I pay to fix a phone that is clearly a manufacturing fault!!!! After leaving my details at the Samsung Head Office regarding this issue no one has even bothered to phone me back..... Don't think I will ever be able to buy any Samsung product again!!!