Ebay: Is this a scam?

[No Chance Without Batman]

I bought an action figure from a seller online, but it was broken. I asked for a refund and the seller said he would send me a replacement and I didn't need to send the other one back, but I need to give positive feedback before he sends it to 'ensure I'm satisfied with the solution', because apparently me agreeing to it wasn't proof enough. I find this kind of dodgy, but maybe they just want to avoid getting negative feedback despite fixing the situation.

Does this sound like a scam? If I leave positive feedback, do I get to change it later/ am I able to report him for lying about it?

[Fred]

Do NOT give positive feedback. Tell him to refund or you will report him. Once you give positive feedback you have signed away your rights.

[Kittysue]

If you leave positive feedback he won't do anything and you can't get your money back. He's trying to scam you. He knows that once you leave positive feedback you can't then file a dispute claiming the item was broken
Tell him that you have no problem giving him positive feedback AFTER you get the new action figure and will post the positive once you receive the new item and make sure it's in good condition