ipad mini battery problem

I just got my ipad mini 16gb wifi + cellular from an apple reseller, not from the apple store because no more stock available for 16gb wifi+4g. i just knew that, like me, there are also ipad mini users that are having a problem of the battery that wont fully charge. i already charged my ipad mini 3 times from a low battery status since i got this. The charging stops at 91-93 % in my 1st and 2nd charging session. the last time i charged(3rd time), again it stopped at 91%, i read a reply from a battery problem discussion that rebooting may help by holding the home and sleep/wake button. so i did and after it rebooted the charging continues from 91 to 100%.

I also read a reply that the cause is due to the adapter that gets too hot which lets the charging stop.

I'm not really sure which solution helped my ipad to be 100% fully charged. the rebooting or letting the the adapter cool down that gets too hot.

I hope it wont happen again in my next charging session, if it does it would be really annoying, rebooting it everytime i charged and i dont like it(of course who does)

I know this has been discussed by many ipad mini users. I discussed this again because i have a question to be added.

Will the apple store entertain me and let my adapter be replaced even if i bought this from an apple reseller not from the apple store?

the reseller told me they only had 1 week replacement.

or will the reseller contact apple and order a new one for me? i bought this 4 days ago, about 3 days left