Unable to relax, has some vanilla tea served (3,2,4)
I believe the answer is:
ill at ease
'unable to relax' is the definition.
(I've seen this before)
'some vanilla tea served' is the wordplay.
'some' says the answer is hidden in the clue (some parts of the word are used).
'ILL-AT-EASE' is hidden within 'vanilla tea served'.
'has' is the link.
(Other definitions for ill at ease that I've seen before include "Elite, alas? (Anag)" , "discomfited" , "Unable to relax" , "Nervous, uncomfortable" , "Unsettled, anxious" .)