Hello, i was wondering can the battery on those smartphones wich is stated non-removable be exchanged with a battery that has bigger mAh? i got 3000 but its not simply enough... I checked multiple battery amp meter programs and the yall say the battery is 1000mAh but im not so trustfull on those programs.So the question is can it be replaced with more powerfull battery of the same voltage or no? (i doubt the seller would want to do that if i send the phone to him)