You texted groom, left alone at buffet? (7)
I believe the answer is:
uneaten
'left alone at buffet?' is the definition.
'uneaten' can be an answer for 'left' (I've seen this before). I'm not certain of the 'alone at buffet?' bit.
'you texted groom' is the wordplay.
'you texted' becomes 'U' (text abbreviation for 'you').
'groom' becomes 'neaten' (synonyms).
'u'+'neaten'='UNEATEN'
Can you help me to learn more?
(Other definitions for uneaten that I've seen before include "Make an outline of" , "Not taken in" , "Not consumed as food" , "still on the table?" , "Left after dinner" .)