I'm new to all these photography things and I just bought a holga 135 bc a month back and just got back my developed photos. But it turned out only 5 were developed!! Other parts of the film were blank or just black patches. Most of the 5 surviving photos were used with flash. I used a Fuji roll of film which I thought all along was a negative film, yet when I went to the shop to develop, the lady said it's a slide film, so she suggested cross-process. I wanna know what's wrong !!! (( Help me!