Really needed on servers.

You pressed F2 twice and it didnt help ? is flying enabled on your server/local game ? if so press F2 once and you will stop falling and you'll be-able to fly. otherwise if flying is enabled f2 twice will lead to your death. but if flying isnt enabled i believe you should be=-able to tp to the surface with F2 twice.
Ps; ive heard that on on computers with preset or whatever you may have to press the fn then F2 . but im not entrily certain. Good Luck.

Quote from theenoid

Temporarily disable losing your things in inventory until you can fix falling thru the world! I fill up in a cave and while heading home fall thru the world, die and lose what I spent hours collecting! (That was yesterday) Now today, same problem. It's very aggravating. I don't even think of it being fun to do it again.... It's not like I can retrieve my corpse. The "F2" trick didn't work. Why not disable it until you can fix this bug?

If the server host. The one who generated the world disabled F2 then their is no work around except go to a different world that does have F2.
You will also notice if you check out other servers that not 1 server is alike. Each one has different options and there for my best advice to you bud is (check out other servers).

If your not wanting to leave this world your at then contact the (((SERVER HOST))) and ask if they will add this option F2.
If you not wanting to leave because your friends play there than go check out other servers together and you all may find one ya like

Had the same problem today, f2 worked for me though.