In our village there is a local pub where there is held a carnaval evening with stand up comedians and other entertainment. The stars are local people from our village. 

On evening during the show the owner Rien stepped forward and stated: I want to sing a song on the podium.
His wife Jean stepped in: Rien, please don't. You are the worst singer ever! People will leave!
So what, said Rien, they already paid for their tokens! 

Sad to say this is an attitude i see on many online services. They forget all about you once you have paid. There is no or very poor customer support. 

LOL this was a joke of course, In fact he does not sing bad at all and in real live Rien is very good in building a relation with his customers and maintain them. That is the reason why he takes part in local events. And as opposed to this joke in real live he is very aware of the fact that when his customers are happy they will stay longer and buy more tokens. And will return for the next event.

Of course this applies to online business as well. Try to answer support questions in a timely manner. Try to make your customers that are happy. Try to find reasons and possible solutions when a customer is unhappy.