In the meantime, use some Velcro tape to tie it closed from the inside. I once had trouble with my then brand-new motorhome's side door not latching properly. Had it adjusted twice by dealer. Still could open it even with both locks locked. Complained to factory customer service via phone and email as I was driving alone through Wisconsin, Iowa, Nebraska, etc. Tried to find dealer who would really, really fix it, but even factory customer service could not get anyone to fit me in their tight schedules.
Short story: door popped open when I hit a bump in Rocky Mountain National Park at 55 MPH. As it slammed against the side of my motorhome, the automatic steps deployed and hit a log on the edge of the road that the park service had put there to prevent people from pulling off to view elk. Bottom step was not 4" to the rear of top step so it would not retract. Door was not damaged, but vehicle not driveable with step sticking out. Fleetwood paid for having it removed and getting it banged back into shape. Gave me new steps but that took 8 months!