Can my moment be killing batteries? (not about battery life)

[budgey]

My phone died, couldn't charge or turn on. Took it in, they tried to charge my old battery on their charger and it wouldn't they said it was junk. Its only 6 mo old. They put a new battery in my phone (a used one from the store) and the phone turned on and worked great. It charged in the charger at the store, in my car and at home. It worked for 2 days and the same thing happened. Took it in again, battery was junk, got a new one phone turned on, worked fine, charged in my car... then it randomly died on teh charger with a full charge and won't turn on.

I'm sure when I go in this 3rd battery will be junk. Has anyone heard of this happening? I'm assuming its the phone