Iphone 5s won't charge properly, help!
Last week I started to notice issues with my Iphone 5s (over a year and a half old) which has been going on for a long time. It started for a few weeks, when the phone was on charge and if I used it the battery percentage wouldn't always increase, then it started to decrease when I was using it, even though it was on charge. Then it got to the point where if it was on charge (the phone would recognise it was on charge with the symbol) the battery percentage wouldn't increase, it would just take a longer time to decrease. Then last week it got to the point where I would have to wait till it was full out of charge before charging it back. I went to an apple store today and they cleaned the charging port from lint and in the store it got to around 5% battery. Now I got home and put it on charge it slowly rose to 5% before stop charging, so I unplugged it and re-plugged it. It got to 13% and now it's just slowly decreased down to 10%. I have two different chargers, so I'm pretty confident it isn't a charger problem. I am also pretty sure there's no more lint as I have continued to try and remove as much as possible.Like I said, the phone recognises the charger as it vibrates when plugged in and the symbol shows, just the batteries dying. Please can someone help me, I'm starting to go mad by not having a phone anymore!
P.s. I have also tried to restart it when it's on charge by holding down the home and power button, doesn't help.
iPhone 5s, iOS 8.3