This is absolutely outrageous. I have repeatedly reported our resident shill bidder for listing in the wrong category. She lists her Nepalese paintings under the Aboriginal paintings category. She also lists under antique art and then says the paintings are new and produced in the 2000's. You guess it, not one single listing has been removed, EVER. 

She gets reported for putting links in her listings. They stay. She gets reported for keyword spamming. They stay. Maybe you need to flounce the rules and say to hell with it. The scammers seem to get away with constantly breaking the rules, maybe that's the road you should head down.

I'd set up a few new accounts as shilling accounts too, because it seems that shill bidding is acceptable these days.