Level 20 achievement

[wwskennis23]

I just upgraded to lv 20 but i found i cannot get that achievement! I am using 3rd gen ipod and was using wifi connecting to the internet! I dont know why I can't get that! How can I get that again except resetting my character?
(I finished the whole game with 4.0 version and found there was achievement thing and upgraded to 4.2 while i reset again, but now some achievements are missing!)

[enigma7x]

There are some known bugs with the achievement system that the devs are looking into. Hang tight until next week's update. It might fix your problem.