dude..
you better go report police ASAP..
these guys steal road tax and put on stolen cars, make same number plate as yours and drive aronud..
my fren car kena same thing like you.. end up his fren saw "his" car with other ppl driving.. so called n check if he got lend his car anot.. found out that his car is at home still with a broken window..
so call police to catch him and found out the car is stolen and they using his road tax and new number plate..
so they steal an exactly same car (same color, model, cc) and steal some1 elses roadtax.. and make number plate and drive aronud.. any saman will come to your house..