He advises the chap to give you the money (6)
I believe the answer is:
teller
'he advises the chap to give you the money' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
This is all the clue.
Can you help me to learn more?
(Other definitions for teller that I've seen before include "Counter of votes or a bank employee" , "One introducing relation" , "Bank official or reporter" , "one gives relation" , "Bank cashier or narrator of story" .)