Crazy Deals

Purchased a massage chair off of the Offer Up site where the seller described unit as new/unused/perfect condition. I stated in message to seller if the chair was as described " new/unused and perfect condition" I would offer $1,000 which was accepted. Picked up chair brought it home and immediately had issues with the chair. The unit would start massage program and the shut off immediately. I have had 2 of these chairs in the past and know the operation well. I immediately notified the seller stating I trust you thought the chair was new and in perfect condition but it's not and I described the issues, I also asked if I could return or at least get a partial refund. Her response "all sales are final done deal" I contacted Offer up and they say since I paid cash they can not get involve to which I feel is so unfair as there description stated the chair was new and in perfect condition. To me this is not only a bad business practice but fraudulent.