Ni there Nsa162, agree with prior posters, sounds like confusion on the part of the sellers attorney/seller. You have closed, proceeds disbursed, check to septic in hand - title transferred. No, don't think terms can/should be negotiated after the fact.
But, these are details of the negotiation and closing that we agents can only offer our general feedback and opinions, but negotiating and documenting points like this prior and through close is exactly why you have an attorney - talk to him/her pronto. Hopefully in the process the attorneys captured this agreement in writing.
Good luck to you.
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