Nearly any company will instruct the lowest level customer service people to say "No," when you ask for a refund. Or anything else, for that matter. Practice this statement, "That won't work for me." Use it, pleasantly, three times in response to the No. If you continue to get the No, then ask for the person's supervisor, again, pleasantly.
I've gotten refunds from all sorts of places, being pleasant. OTOH, I never joined classmates.com, because it seemed a waste of money to me. That said, I would venture that it's harder to get a refund from Comcast, and I recently got two months service credited, d/t pleasantly complaining, high enough on the customer service ladder, about poor service after a storm.
The way you approach people matters. Check your attitude when you're trying to get a refund. Assertive =! aggressive.