I forced the issue with Earthlink a while back and they contended that you have to have a special promo code in your user profile (on their billing system) in order to receive the credits. I have been an Earthlink customer for a long time, and after about 3 days of back and forth I got them to send a request to RR that I be credited for the 8.
Their original offer to me was that they would add the code to my account, but I would have to remain a customer for another 6 months of whatever it was. This was unacceptable to me since I had been a customer for so long anyway. Also - they screwed up and didn't get my RR# added to the account so it took a little longer than I hoped.