Retro fitted rear parking sensors

[duckpond]

I have problems with the sensors fitted to my 6 month old C Class estate. The sensors were positioned below the site for factory fitted ones and has resulted in them picking up the road.Has anyone slse had experience .Oh I paid mercededs to fit them when I brought the car but the work was sub contracted

 

[ralph]

Sounds like a 'not fit for the purpose' complaint.