I had a piece of flannel like fabric - I think it had polyester in it - and it smelled of mothballs -
I did everything I could think of to get rid of that smell - got it tamed down a little bit - but after about ten washes and ten days of airing out - I gave it to the neighbors to throw over their plants when we got freeze warnings. Told them to bag it and store it UNDER their shed.
Good luck! I think I would take it back.