Help!!!!! iPhone 5s isn't working!!

Hi, so my problem started off about some months ago when I accidentally dropped my phone, which caused a minor damage to my phone, and I doubt that it's the thing that caused this problem. About a week after that I updated my phone to the newest one, and the day after that my phone stopped charging. it only charged up to 10%, but charged to 40% after about 24hours. After A while it didn't charge more than 1%, and soon later died, which i knew i had no more chance for it to 'live'. Apparently after the update it has happened to many people (?) So i left it at a phone place to ask them to see what's wrong with my phone, and after an hour or two i went back and they said that there was nothing more they could do, and the phone wasn't able to fix. I left it somewhere else to get it sent back to apple and then get a brand new phone, but they didn't give me one. Anyway, I recently tried putting the charger in again, and it went into the starting/booting mode ( The white screen with the black apple logo ) But it stayed there for hours and hours. Nothing happened. I tried connecting it to iTunes, but it couldn't connect. PLEASE HELP ME I NEED THIS PHONE WORKING!