Buyer filed claim that they did not receive items, but tracking numbers say item delivered

[peaprom-0]

I recieved a message from my buyer a moment ago that they did not receive package but the tracking confirm that it was delivered left with individual (plus they contact me back 2 week after it was listed as deliver). I contact him back immediately with tracking number, asking their family on the receiving date and contact their local PO. but they replied that instead of recieved my package they recieved a box of something else which it was not my selling item at all. Do I have to do a refund? But if so I'm gonna lost both my package and momey.  Is this kinda a scam? What should I do about this case?

Thank you for all of your respond. 

[peaprom-0]

Sorry for my broken english. I was hurry created the topic to find the resolve of this incident.

[johnrj1226]

It is a scam.  Don't engage in any further discussions with the  buyer.

Add the tracking number to  the claim the buyer opened.  Then  call eBay and  get the case closed in your favor while you are on the phone.  Be certain to tell eBay the buyer changed   their story - first  didn't receive the item and next  the item was different than what  they ordered.