Lost tracking recipt what should i do?

Hi sold something and payer paid me through paypal

I shipped and got travking however i lost my tracking number..

Now the buyer is saying item not recieved when i know i sent it.

What can i do? I dont want paypal to refund the money and me be out the money and the item…

It was listed on fb marketplace

I lost the recipt, i didnt get an email, and forgot to send to buyer, it was a busy day.

so i guess ill count it as a loss 😌