You may be able to repair the lock. Remove the red plastic cover on the small knob. Remove the screws that hold the inside cover on. Remove the inside cover. Install the key. turn toward lock and unlock and see why it is not working. If a part is broken you may be able to take it to a RV lot and find a old lock that was saved for parts and purchase the bad part. We always had a box of old locks at our lot.
1998 Pace Arrow 35 ft. F53 Ford V10 2012 Honda Civic toad
32 years mechanic at Delta Air Lines 15 year motorhome service manager. 3 popups....2 travel trailers....5 motorhomes....loved them all.