yesterday I just update my os into 10.3.1 after that my battery is getting down,now I try to switch it on but it just on and the battery level is getting down like 9,8,7,6....0 what is the solution for this
Well, you could charge it and see if it settles. You hopefully have a backup, and could go back to an earlier OS. Or you could do a factory reset. Or you could sell it on ebay as-is...