sounds familiar
i actually had a lost logbook type incident with the caa before...
i dhl-ed my logbook etc to the caa and after a while, i hadn't heard anything back from the caa. so i gave them a call to check all was in order and was very promptly told nothing was ever received and that it must have been lost in the post.
so i nearly had a heart attack thinking my precious documents were lost forever....i called dhl and they traced the package. it turned out that it was signed for at the caa on a certain date, time.
i called the caa (and got the same guy) and he denied point blank that anything was received.
i argued with him and told him he had better do something and fast as it was "missing" and it was through no fault of my own.
a very short time after, the package was found in the office, unopened etc.. and they had the items for over a week.
i find the "lost in the post" thing very dubious and would follow it up. afterall, if i had not been pushy with this guy, i probably, would have received my licence sometime next year!!!
good luck and i hope all works out well for you