door locks

[BLACK6N_POLO]

the left door on my 3 door 6n is playin up -- it only happen today --- when the key goes in it unlocks the door but when u pull the handle it does not open the door -- ocassionally it does catch on and open --- ive been told its a plastic clip sorta thing and i can gt it off another vw without having to buy a whole new system- has any one else experienced this --was it expensive to sort out???????