I have had this happen to me last fall. I drilled out the key cylinder and then put in a flat head screwdriver and turned the dead bolt to turn to open the door. Yes you will have to get a new cylinder. I used a bit a little smaller than the cylinder size. I had contacted fastecindustrial.com since they have had a problem with these key cylinders and they sent me 2 cylinders with keys. They also sent me a special key to put in the new cylinders. Real easy to do. You can also go on rvlocksandmore.com and order extra cylinders with the keys. If you do not get the special key you can take the handle off the door and lock the new cylinder from the backside of handle. There's a clip on the cylinder that locks in the back side. You can also order a whole door lock handle with new keys from rvlocksandmore.com