In my experience:
Hills: Superb service, instant answer on the phone and friendly, helpful and knowledgeable staff. They even voided a bet for me when I had backed the wrong selection by mistake. Thought the best I could hope for was them changing the bet to the correct selection but they left that up to me. Said he could see from my record that I was not a chancer. Full marks.
Bet365: Only called them once when I was confused over the terms of a free bet. Not for long. The girl who answered knew the business alright and soon clarified it for me. And who else has senior staff monitoring this board and responding to posts, generally within a couple of hours?
Betfair: A waste of time emailing them. What use is an automated response? If they think that makes the customer think they care about them then they need to think again. The only response I want is from a person. I would only ever phone now and then it is a bit hit and miss. You might get someone who knows the business or you might not. Way to go yet I think.
Ladbrokes: Shockingly poor for such a big outfit. I called one day because I was unable to place a bet online. Suddenly, after years of using it, I could only view markets when logged out. I was told there was nothing wrong with the site and this without reference to any technical personnel. Well if you can't help me troubleshoot this problem I have no choice but to use a competitor" I said. The reply was basically please yourself.
As for the rest of the UK online bookmakers I have never had occasion to use customer service and that must say something for them
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