If it's your name and address on the parcel then I can't fathom how it is a mistake on any seller's end.  Wrong item, yes, but they couldn't have pulled your name and address out of thin air.

Just to check, you know it's to do with ebay because it's in an ebay satchel or has an ebay label?  If that's the case, have you tried comparing the tracking numbers in your purchase history with the number on the parcel?

IF it really isn't one of your purchases, then eBaby may be able to link the tracking number to an item id and hence the seller.  It would have to be on the system, question is whether ebay will give it to you.  I'd be asking family and friends otherwise.

Buyers aren't given sellers' name and address details unless they request them, so unless a seller puts their User ID on the parcel (most don't), then you don't know until you open it.

You've got a long enough purchase history, why is this one different?