Is this an eBay scam?

[Hogu]

I bought a phone on eBay but when it arrived it wasn't in the condition it was advertised. I opened up a return request and seller offered me around partial refund to keep it! I accepted the partial refund as it meant a £400 phone only coat £40!
Now they've refunded me they are saying it was a mistake and I need to pay her the money back straight to her PayPal account. I can't reopen the case as it automatically closed but I'm not sure if this is some sort of scam?

Just ignore it and block.

I'm not sure if it's a scam but that's alot to refund for a phone if its in working order and worth £400 so it's likely to have been an error. I would wait for ebay to get involved they can initiate that you refund if they feel its warranted or decide that the agreement cannot be changed.

Definitely don’t give them the money back!

Just ignore and wait to see if Ebay contacts you.