Google has lost its final legal challenge against a European Union penalty for giving its own shopping recommendations an illegal advantage over rivals in search results, ending a long-running antitrust case that came with a whopping fine
Additional fines and, if necessary, sanctions. If you refuse to pay a fine imposed by the EU then guess what? You can’t do business in the EU any more.
They could force ISPs to block, not allow physical hardware sales in stores, take over any assets (offices), confiscate their server farms. There's lots that can be done.