I recently tried updating some of my levels whilst connected to bad WiFi. I tried again with decent WiFi, and now I cannot update due to errors, and two levels have disappeared from 'my levels' Is there any way to fix this?
Sorry, happened to me before, it's not fixable. The best way is to copy your entire level, create a whole new level, paste it there to save it as a new level and reupload.
WARNING: THIS MESSAGE CONTAINS NOOBISHNESS! So how would I copy a world? (I'll try find out myself, but this message is just in case I don't..)
Rectangle select every single thing in that old level of yours, save as a group, then paste the group into the new level. If your level contains a lot of things, copy, save and paste part by part.