Help with scratches in black spa surface

[jurmanji]

Hi All,

Was hoping for some help/advice.

We just put in our spa and there are already scratches on the seat and bottom (see the pics). Our builder says that's totally normal. It doesn't look normal to me, but I've never had a dark plaster spa. Would love some opinions. Is there a way to fix it? Should I insist he re-plaster it?

Thanks!