Well, it appears that Parago just picked up the Bitdefender account from the company in White Bear Lake, where they had been for quite some time. Perhaps their showing that they are able to identify and crack down on resellers was a selling point?
Yeah, this could be a concern. At least the history from the old processor would be wiped clean, theoretically.
May not get wiped clean. I'm sure that Parago can ask the old rebate company to provide a database of all of the past Bitdefender rebates that they processed.
If the rebate houses are competing for business, I doubt one processor will just happily provide their business records to a competitor, especially one that just poached a client. They may be contractually obligated to, or may have already given said records to the client themselves, but they're not about to do so just because the new processor calls and asks.