The email thing is a known problem that WK has been trying to solve.
It doesn’t always work, but if you go into you WK Dashboard settings, and toggle the e-mail option off and back on, it often gets back on track.
If there are people that would like to know what missed emails said, while looking for clues for the 2018 Christmas riddle, a thread was created where the content of all 60 level-up emails has been gathered.