I'm looking for a word that would clearly designate a person who takes individual payments from individual utility customers (e.g. his neighbours, friends or family) and goes to the utility (e.g. telecoms operator) payment office to pay in the global amount on their behalf.
He or she does not do this as an occupation but rather to help his fellows villagers (e.g. in a large country where the Points of Sales are sparsely distributed) and is himself a subscriber of this utility (albeit authorised for this role).
I would prefer to avoid payment collector which is altogether a different role in most utility jargons.
In addition, I'd also be willing to take suggestions for the individual payers (better than contributors for instance).