eR1c

iTrader: (2)

This is tough as there are lots of variables, batteries are not something I'd ever purchase used.
But since you did,
-Your not sure if it was puffed when you got it?
-So it could have puffed after you charged it in that case.
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I can honestly see both sides here, either the seller scammed you and sold a bad battery that was already puffed (which is totally wrong and not even safe to mail in my opinion).
Or you puffed the battery by charging at too high a voltage or amp setting (I once accidentally charged a brand new Reedy Zapper at 30amps and it puffed like a hot dog ...split right down the middle).
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I think you will have to suck this one up. Lesson learned.