Coating with a large area of foliage

Hello friends, from the front: I know 0% with varnishes, paint etc.. Today in the parking lot much me a funny color on the rear bumper, behind the rear right wheel box, below. I then went over it with a damp cloth, to see if there is a scratch or something, and then a large piece of paint just peeled off. Then I drove into an SB box (not thoroughly, but just so that I can look at the place more closely) and at the Waschen then fell off a just as big piece, which was already easy after the waste of the first piece. I put pictures on what it looks like now. My questions: a) How can something like this happen? Damage fixed and grottig lacquered? b) Can I repair something like this reasonably okay? Of course, the white one looks really bad. The place looks almost only when you kneel on the floor and look under the car. Standing there is only easy to see the white one. So it doesn’t have to be perfect. However, I now have two different heights (even where the varnish has been peeled off it is deeper than the rest). Do I get something like this with a base varnish + clear varnish spray set from Ludwiglacke to and then grind and polish to adapt or does it require more work? Mercedes C-Class Year 2000… Metallic varnish!