I probably have 9 or 10 online accounts mainly due to promotions etc, the only ones i have had customer service dealings with are
ladbrokes,
bet365 and Will
Hills.
All were ok but i would have to say
Bet365 were most professional and quickest with most problems solved within a matter of hrs.
I mainly use
Bet365 and
Betfair now and so far have had no customer dealings with the latter as most problems are mentioned in their chat forum (which is an excellent idea) so an email is not normally needed.