Fortunately I may be able to shed light on this issue. I had the same issue with EarthLink ISP.
My card info was not an exact match word for word as my EarthLink Account. It was joint account. I used my personal CC to pay for initial service charges. Since the info didn't match to the T. EarthLink was not realeased payment. My card service placed a hold on the funds I requested for EarthLink. When they didn't actually recieve the funds, they interruptedone my service. Which resulted in me trying to pay them a second time while unaware of the current hold. So I ended up with duplicate charges for the same account. As I had never used that CC for EarthLink b4, the anti fraud protection kicked in on the second try, to "investigate" a suspicious transaction. (Which is fancy BS for "We'll give you three days to call us and say you lost your card. Hope your account doesn't screw itself with auto debit while we freeze all