iphone 5 battery percentage does not update and it frequently restart

Dear Apple

I have been a great fan of your products but i am really sorry to say that iphone 5 has been a failure for me. I bought a brand new iphone and it fell just from the height of 1 feet but the lcd soon got damaged. And i had to replace it. I then bought another iPhone 5 (refurbished from Apple Store) and it has been just 3 weeks. I was at a function at my school yesterday when the iPhone got very hot and the battery percentage remained 91 % for about one and a half hour. My friends suggested me to factory reset the device. I factory reset my iPhone and after it the battery issue remained same and now the iPhone also restarts frequently. I am really in a fix as I had to sell it yesterday but due to this problem no one is buying the iPhone. Please help me!!