The case you highlight above looks more suspicious, but as you’ve already said, there could be loads of other explanations.

Rather than just canning the merchant, I’d look around to see if other affiliates have highlighted similar problems, and see how well their overall EPC / EPM compares with other merchants.

As Clarke says, it ultimately has to boil down to trust. There will always be some merchants who will try and duck out (sorry, a weak pun I know) of paying their dues, but the majority understand that proper tracking = more sales = more traffic = even more sales, and so on

Correct, even Networks don’t fully know. Sadly Affiliate Marketing is about trusting the Merchants, then the Network and then the Affiliate any one of these can be up to allsorts of funny business.

Also cash back sites are not bullet proof, you have people that use cookie blocking software trying to work out why the cash back site not working for them. Or want to be fly guys who log on to 2 or 3 cash back sites click all the links in hope of getting commission on each.

The thing is many a time you just know something is not right but you can’t always prove it so what do you do when that happen.. Simply save the grief and go promote one of the competitors, no point in moaning about it unless you have got hard facts (often difficult to come across without recording and doing a transaction yourself).. Move on = Happier life.