Know exactly how this feels.Had this done to my last car,an Audi S3.
I did manage to machine polish out most of it,but there was a line on the front wing where it was deepest,so that had to be cut back and painted.
On the plus side,the police arrested a local scrote on other charges and he copped to keying it whilst going to an address further up the road from me.so I got to know who it was at least,although I never got an apology or reason.
Take it along to a detailer or a good bodyshop and they'll advise you best on what to do.
Good luck!