You have let me down Samsung

I bought a samsung galaxy S7 Edge 2 years ago from my bank. In this period my phone has not fell once, does not have one scratch on it. It literally looks brand new. I have a samsung tab a as well so dont over use my phone which is why I find it extremely odd that my battery would run down all the time, due to this I find myself charging it like 3 to 4 times a day, the reason i bought this phone was due to long battery life. A friend of mine bought the exact phone at the exact time and has several apps yet mine seems to be defective. the battery has swelled causing the back of my phone to slightly open and lasts now for about 5 minutes if im lucky and thats if I dont touch it all. So now its out of warranty and the cost to have this fixed costs the same as a brand new huawei . Is this the reason why everyone has that brand instead of samsung? A brand i trusted my whole life, finally dissapoints me. R17000+ later im sitting with a dud of a phone . Do i repair it due to the cost of this phone even though it will not be water resistant or do I just change my brand? Extremely disappointed Samsung ! You have let me down !