Hi Dave,
I think you are missing out a few key facts here.
How do you provide, or want to provide, the support? Is it telephone, online chat or email? Perhaps all of them.
What sort of follow up system and logging system do you need?
Do you need reports to track your customer service rep's productivity?
What exactly is the nature of the support you are providing?
What is your budget?
There are lots of nice and free web based systems out there. I use an open source system and it works very well. The only software I paid out for was phplive which cost me £80 as I liked some of the features. I didn't have to spend out on this though as suitable free alternatives were available.
Here are a few links to some free open source systems. If you are not a technical person then get a techy to set it up, it should not take long.
OTRS::Enterprise Open Source Trouble Ticket System - Service Support System::Welcome! Open source trouble ticketing: SimpleTicket osTicket:: Open Source Support Ticket System
If these don't suit your needs then just google for more or check out the main script sites as they have lots there.