If you still have the G500 (or anyone else who has the double click issue), you can try taking it apart and cleaning it. Mine started to do the same thing about 6 months ago. I followed this guide to clean the metal contacts: …intricus.net/…/how-i-fixed-my-logitech-g500-mous…
I didn’t do step 4 to remove the leaf spring and followed the advice in the Warning section in step 3 instead. It surprisingly worked and I’m still using my G500 now without any double clicks since.