I've lost certain channels on a sat

hi, im not that tech minded with a motorised vu duo.I was flicking through my Sat's last night and I noticed I've lost 13deg. I played around looking for it but couldn't get it. Went back to 28deg and I had no channels. I had the foresight to take photo of all setting before I altered anything. But my channels on 28 only some are highlighted. I've been on this for 4 hrs now and I've got nowhere. I'm guessing it's a lnb selling I've got wrong but I cant find which. All my favourites are saying n/a. I can attach photos if need. Thank you:linuxsat-happy-new-year :