unsatisfied customer

I have a retail tile store and a customer does not want to accept the tile that she special ordered although she signed the terms and conditions policy that we carry saying the following: "Most of the products are hand-made and/or hand-painted, therefore they can present variation in tone, size and texture. We do not accept claims of any kind due to these characteristics".
The tile is beautiful the only thing is that the tone is a little lighter that the one we have in display, although it is from the same manufacturer. That is why we specify that it may be a variation in tone. She does want her money back, but we already paid the manufacturer which does not accept returns because it is a hand-painted product and it is made for that specific customer, also the tone variation is within our variations acceptance code between the manufacturer and us (the reseller). What can I do?
Thank you,
Marisa

You can refuse and if she wishes she can go to court. If the variation is not great, she will not prevail.