Bike Description

The bike has mudguards, and quite a few markings on the frame as I usually have my lock there when I cycle. There are also markings on the saddle bar as my back light used to be there.  Tires and brakes have been replaced fairly recently, I have also changed the gears. UPDATE - found the bike on gumtree.  https://www.gumtree.com/p/bicycles/cannondale-quick-disc-1-2017-rrp-£775/1382812418 I have contacted the seller (even confronted him that it's stolen) but don't dare to set up a meeting.  How do I get my bike back...