How would you respond to an A-to-z claim for 1 of 2 items not received?

I have been selling on Amazon for a few years, but have very little experience with A-to-z claims. I had a buyer place an order for two shoe laces on Dec 18, 2022 , which were shipped together in the same package, but the buyer opened an A-to-z on February 19, 2023 claiming there was only 1 of the 2 items in the shipment. We received no contact from the buyer prior to the A-to-z claim. I have already inventoried this item and verified the weight of the package to confirm we did ship 2 laces at the time the order was placed. I am not concerned about the cost of refunding the “missing” lace, but I am concerned about this claim affecting our ODR. How would you respond to this claim?

Order date: Dec 18, 2022
Shipment delivery date: Dec 22, 2022
Claim date: February 19, 2023