Did the re gas include a check for leaks? Recently had mine re gassed by Halfords, next day not cooling, took it to an independent air con place and matrix had a whole in it...fgs, even though Halfords said the pressure was holding fine.
Citroen are doing a air con service which includes a pressure check before re filling....and its the same price as Halfords
Its a fairly basic system and it takes a while to cool, but mine is fine if I leave it on long enough.
As said, recirc mode helps to cool a hot car initially but leave too long and it gets stuffy. Lastly of course, don't open any windows.
I would have thought if the pollen filter was that clogged, the air would be cold, just not much of it.
MkIII VTR 1.6hdi Modutop, Climate Pack, 16" Alloys