Film always blank after shooting?

I have an Olympus OM-10. Looks great, everything seems to be working fine. But the problem is after shooting a roll. This is the second time a shot roll is coming out blank in development. I gave another roll, shot on a Nikon FM, to develop at the same time, and it turned out fine (so I don’t think it’s the studio that develops the rolls for me). The camera repair person seems to think everything is fine with the camera itself. What could be wrong?