There’s no magic bullet here.
You aren’t an ******* for returning a bass that weighs more than you were told.
But.
I’m not clear why you didn’t check this before making your offer.
If your offer and acceptance would be contingent on weight, you should have checked first. Especially since an accepted offer is, per tos, an obligation to buy on your part.
If you had done that it’d be open and shut.
That all being said, Reverb will side with you because “not as advertised”.
This may be a situation where paying for your own return would be the best way to clear any hint of wrongdoing on your part.
You aren’t an ******* for returning a bass that weighs more than you were told.
But.
I’m not clear why you didn’t check this before making your offer.
If your offer and acceptance would be contingent on weight, you should have checked first. Especially since an accepted offer is, per tos, an obligation to buy on your part.
If you had done that it’d be open and shut.
That all being said, Reverb will side with you because “not as advertised”.
This may be a situation where paying for your own return would be the best way to clear any hint of wrongdoing on your part.