2003 Hyundai Elantra Door locks

I hope that someone here can help me. I have a 2003 Hyundai Elantra GT and I can't lock one of my rear doors. The dealer told me that I need a door lock actuator but after I get there and pay for the part, I'm told that the part is on a national backorder with Hyundai. How is this possible? How am I supposed to be able to lock my door without someone breaking into it and robbing me blind? Please help.