What car ? Happens on e36s quite a bit..easy to sort but not on your first go its a mass of springs and collars inside the barrel. .will your key come out ? only option I had was wheel off..ignition off. Barrel out disassemble, bought repair kit from ebay for 11 quid..replace and reassemble..bmw want 280e for the privelage..if you wiggle the keys around very easy it may catch but its a temporary solution to a long term problem