Customer return ... quality.. now it's damaged

Item delivered 9 days ago… customer opened return 6 days ago stating wasn’t happy with quality… Return is auto approved but is a Hazmat (not sure why but anywho) so Amazon didn’t return a provide a free return label for this change of mind… 6 days later the customer is now saying of I was unhappy with the quality AND it arrived damaged… despite making no mention of this previously and only now doing so after seeing they have to pay for the return postage… What’s the best options here?