I finally got Joker avoiding scalpers just to get my first defective part :((((

The shop told me to contact Good smile company and fill a form, so I did. If I don't get my replacement part because the nendo its too "old" or another reason, I'll definitely ask for a partial refund to the shop.

So my question is, how can I fix this? Can I file the joint? I don't care to erase the paint since it's the joint/head section that cannot be seen. Any other suggestions? I won't do anything now but I would like to know my options.

Also, what partial refund sounds reasonable for you to ask?