Recently active topics in Tom Tom tagged with new unit

I just exchanged a TomTom One 3rd edition for a new one (same model) at Office Depot where I bought it because the first one was defective. The one I have now works fine (yeah!) but when I tried to use the TomTom Home feature allowing me to download the latest maps, I was told my account was already set up to accomodate the first unit and I wasn't allowed to change my account to reflect I wanted to use the second unit. I got an error message saying something like I can't change what unit my account works with more often than once every 6 months. And NOWHERE can I find a customer service number to CALL. What do I do?

Jeff Vaughn