My phone's condition now is a bit tricky, the battery has got some problem, after playing some games leaving it to around 10%, phone switched off itself and when i charged it from PC's USB, the phone which was already off had only 1 %, when it's 1% i cannot restart phone.

So i waited and later checked that it was 2%, can restart the phone, then just leave it alone and then it swithced off itself again.but still it charges up to 63%, a few minutes later, becomes 81%, i switch it on, it stays still at 81% for a long time and it switches off itself and show only 1% again.

Kindly advise me what to do and it's an ap set, bought this week, thanks!