How to write a thank for you a returned gift?

Someone at our shower but us a pack and play not on our registry. Someone else bought us a pack and play that WAS on our registry. The one off registry did not come with a receipt so my husband’s parents are going to ask for one from the person who bought it. We feel bad but we don’t need two. How do I write a thank you card??? It was so thoughtful but we just don’t need or have room for two!

Also— we don’t know where it’s from. It’s a Disney brand pack and play. Doesn’t show where it’s from.

Both in laws bought pack and plays already.

No one we know is having a baby anytime soon!

UPDATE- it was my husband’s great aunt who bought it. My MIL already called her because my MIL was the one who bought the one off the registry.

So we didn’t ask for the receipt, my MIL took it into her own hands to ask. I tried to tell her we can try and bring it places to return but she already called her. I honestly think it was bought from a third party site on amazon. So we’ll see what happens.

Also- trust me I didn’t want to have to ask I felt really bad. My MIL did. It was very kind of her to buy it. I googled where it came from and a place in CA came up. The labels were on the item itself. I don’t know what stores would’ve even taken it with those labels.