Wireless Devices - beware of roaming!!

I bought a usb device and was charged for roaming when I wasn't. I called customer service and she agreed to reverse the charges. I then received a letter from (Cameron McCuaig - right!?) saying the charges would be reversed. No mention either on the phone or in the letter about Other charges. In fact the letter states it will reverse ALL the charges. Nothing about REcharging me. I then found out on my next bill that I was being charge $100.00 to reverse the charges.