I don't think the issue is specific to WJ. We started changing over the games to Bet365 because of how annoyed we were at what happened and subsequently being ignored. But Bet365 seems to have the same problem and have acknowledged it, and last we heard they are looking into it (that reminds me to follow up with them).
The specific problem is this. If the user clicks play for real and they are redirected via a URL like this then you have a problem:
hxxp://banner.kingsolomons.com/flashcasino.php?language=EN&id=1
&member=&profile=&game=bld&_realonly=1
You may have to use firebug or a http traffic inspector to see where it is going because it redirects several times between different URLs almost immediately. Otherwise click play for real and try to hit the stop loading browser button at the right time.
The key bit is the "&member=" part. If there is nothing there after the equals sign and before the next & symbol like in the link above then tracking is not working for you. I asked both WJ and Bet365 if they were using a cookie instead but it appears not. A day after I complained to WJ it was changed so that it said something like "&member=ouraffiliateid" for us.
Here are some figures to chew on: 294261 impressions, 12 depositors, over the past 2 years. That is a 1 in 19600 conversion rate. I am willing to bet those depositors were referred from the review pages for their casinos as opposed to the free games which would account for over 99% of those impressions (as an aside it would be far more useful to us if they did not record an impression unless someone actually clicks play for real). So either the free games are completely worthless in as far as gaining depositors so we should not bother with them anyway (however we know they aren't from our experience with other providers) or we have potentially missed out on loads of referrals.
The fact WJ changed the tracking link the day after I emailed them (on June 12, and follow up on June 21) clearly indicates that they know about the issue and did indeed receive my emails despite protestations to the contrary. I assume they probably fixed it for everybody that same day but who knows, maybe not?