Classmates.com multiple unauthorized charges after canceling free trial Internet

I signed up for the free trial. I cancelled after 4 days. I continued to get emails from them telling me people were signing my guestbook and I had emails waiting to be read from classmates...but I had to pay for a gold membership to read them. I did not fall for it because the person they said emailed me was the same person I searched for 5 days ago and they were not on classmates.com anywhere. But next month I saw a $15 charge on my mastercard twice. I emailed them to remind them that I cancelled. Then I called. I was assured I wouldn't be billed. But there it was again next month. Now when I call I get an automated messgae telling me to go to the website for help. I am disputing these charges with my credit card compnay.

Alycia
POTTSTOWN, Pennsylvania
U.S.A.