I have the same phone and started having similar issues. It took longer for my battery to charge and it would always pop up telling me to use the original charger no matter what charger I used (including the original one). At first I assumed it must need a new battery so I bought 2 diff batteries thinking the 1st one was defective. (Btw I had no previous experience taking phones apart or anything like that b4 this and I had no prob) but at least in my case this didn't solve the problem. I ended up realizing that my prob was the charging port of my phone because I was having to get the cord in a certain position in order for the phone to charge. It got to the point where there was only one cord that would work to charge it ( i even bought new charger cords but they wouldn't even do the trick). Then one day I had to take the cord with me to an appt and left it there so I was without it for a couple wks and unable to charge my phone and whenever I've tried since to hook that charger to it it still won't evn begin to charge.