According to Tradedoubler's terms, they only pay out to the affiliates when the merchant has paid them. Unfortunately merchants often stall and delay paying for a couple of months. That's probably why you had trouble getting your money.
We had been reporting about that and their laywer had even dared to demand from one of our webhosts to shut down our website.
In the end they apologized and payment arrived after half a year. Even their London office had felt embarrased about what went on in their German branch at that time.