Check out the below website and type your registration number in the box and see if you have been caught on the camera. If yes, then do challenge it by writing to them and explaining your situation. I know that many people have challenged their fines and managed to get them withdrawn. Don’t forget that the violation would normally show up after 3 working days in the moi website.

http://www.moi.gov.qa/TFCViolations/English/EnglishInput.jsp