1999 Volkswagen Jetta

My doors don't lock or unlock at times. Now I have to lock the door several times at the passenger side door. Then I have to use the passenger door key slot to unlock the car. Then once I get the door open the other doors have to be unlocked by pressing the lock and unlock button several times to get all the other doors unlocked. Sometimes when I start the car the alarm goes off and I have to try several things to get the alarm to stop and get the car to start. This is very sporadic and sometimes the key wont start the car 'til I play with the ignition for a while. I live and work in the city and am concerned for my safety. No one knows how to fix it! PLEASE HELP ME.
MH