My user name sagirkedi , and my position was in 25 , and I earned two doom cars , and I used it,from now my doom’s both power up to 4 . But when I quit from The game and login again my doom’s powers down to 3 . What is it ? 
Please contact Customer Support with this issue, unfortunately there’s nothing any of us can do to resolve this for you, but they should be able to clear the air after a few exchanges.