Dead Lock Not Working?

[mulligan-can]

The deadlocking function in my car doesn't seem to be working? When I dead lock it the locks can all still be opened from inside the car. Also the actuators don't seem to move the locks all the way down and occasionally you can open one of the doors anyway? (Only from the inside mind you which is odd, and still worrying).

Also I have to slam the front doors shut as they won't close fully unless I do. The rear doors close easy enough but the front ones don't fully close/seal when you just lightly pull it closed.

[COINERS]

i lent my car to one of my mate once. got the car back and the dead lock wasnt working as well.
id also like to know how to fix it...
thanks guys