Omiacha

Hi guys, I have a 2017 SLC 43 AMG that I've owned for about 5 years and have never had this issue until the last few months. However, when I drive the car for 10-15 mins or more the message "Radar Sensors Dirty See Operator's Manual" pops up approximately every 10-15 mins. I have now had it at the Mercedes dealer 3 times. The first time I had it there for its oil change and they told me the sensors were probably dirty from road grime and I should just wash them real good. I did that and it didn't help. So I took it back and they said it was the distronic sensor behind the front emblem that was dirty. They supposedly removed the emblem and cleaned that sensor. Immediately after I left the sensor came back on. So I took it back a week later. This time they say the distronic sensor is out of calibration and they spent a long time recalibrating it so should be good now. I live an hour and a half away from my dealer and on my return trip home the message came up 6 times. I am so frustrated and fed up with my dealer at this point so I am coming to the forums to see if anyone else has had this issue and if they know of a fix. It is a fairly minor annoyance, sure, you just click ok and it goes away for 10 mins or so before coming back. Minor except that I am looking to sell my car soon and it is going to be an issue for any prospective buyer. I take meticulous care of my car and I just want it in top working order when I try to sell it. If anyone can give me any advice on the issue it would be greatly appreciated thank you!