Years back I signed my ecom business up for ResellerRatings’ similar service for like $20 or $50 / month. Eventually they determined we should be paying a few hundred per month based on their impression of our traffic and upped the price, notifying us at the bottom of a very, very tall newsletter email. It was like a year before we noticed, they quickly refunded us 6 months when we told them we were charging it back (presumably that’s how far back we could charge back without fighting harder).