Customer support

I have just spent a few very frustrating days trying to get hold of customer support for an internet based company. There is no address or phone number that I can find on their web site - just the email address for their help desk.
Well, I have posted a series of questions relating to a payment and a supposed upgrade of my service, but I have not had any reply in the last three days.

How does any company expect to retain its customers if those customers cannot get any help for the products they have purchased? The most visible aspect of any company is its customer support department.