Seller signed incorrect PSA?

[Aharon Najafi]

Buying a property in atlanta. I put a stipulation that said the offer price will increase by $1k increments up to $150k if there is a competing offer.

My offer was $120k and there was a competing offer of $130k. The purchase sale agreement came through showing $120 not the new price of $131k. Both the buyer and seller signed this and there was no modification to the offer price on the PSA.

The seller now wants to amend the price to $131k and my broker doesn’t know what to do.

Is $120k or $131k legally binding?