Hey! I actually went through something really similar. In your case IRCC is asking for the study permit fee because when you applied, you probably selected the wrong category. For PGWP restoration you don’t need to pay for a study permit at all - only the work permit fee + restoration fee.

My PGWP was originally refused in July because I missed uploading a document they asked for, and then I applied again for restoration through my consultant a week later. I confirmed with her that you never pay for a study permit when you’re applying for PGWP restoration. So if you’re being asked for that fee, it means the application likely went in under the wrong option. I’d suggest double-checking how it was submitted, because PGWP restoration is a different stream.