Affiliates being credited with 2x for a single signup for a trial member

We have your affiliate plugin running, and one of affiliates have been credited with 2 x PAID signups, even though the signups registered for a trial which is not yet completed and no payments have been made. This leaves us in an awkward position of having to tell our affiliate that he is not getting his $97 anyway.

Help would be great appreciated as this is URGENT.