FOSS gamedev and creative worlds

I was deeper underground above -245 and i was mining for gold ,mese, mithril and after i get mese and gold i was bored and i wanted to get up but no more surface why there was no more Why??

Because you haven't surfaced? Surface isn't just at altitude 0 (else the world would be flat); it can be above, or below (up to +60 sometimes).

i have tried to go up but the part of that location was deleted and i flied over and over i flied 1 hour but nothing

You were probably going to fast and the chunks weren't loading, or you ran out of usable disc space.

Try respawning.