FBA Purchase

I sold an item through FBA (pack of 15 protein bars) customer has sent me at least 5 emails saying the item didn’t arrive. I have told her to contact customer support as Amazon fulfilled the purchase, but she saying they are telling her to contact me. I am not sure if Amazon used their driver or Royal Mail on this occasion but I don’t believe she has contacted Amazon.

Now the same customer is saying the protein bars arrived damaged and ruined her Easter event and is demanding a refund. I again told her to contact Amazon. They either turned up damaged or didn’t turn up. I know she’s lying she knows shy lying But she’s not having any of it sent at least 8 emails. What should I do ?