Kind of Indian tea service American sent back (5)
I believe the answer is:
assam
'kind of indian tea' is the definition.
(I've seen this before)
'service american sent back' is the wordplay.
'service' becomes 'mass' (church service).
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'sent back' is a reversal indicator.
'mass'+'a'='massa'
'massa' in reverse letter order is 'ASSAM'.
(Other definitions for assam that I've seen before include "Type of tea" , "Indian state known for tea growing" , "State in northeastern India" , "Top quality tea" , "Tea-growing region" .)