Delayed commission means that the advertiser hasn't paid their bill, so the affiliate is left on the hook to eat the loss. Don't expect to see that money. I have nearly a thousand dollars in Delayed Commissions with PJN from as far back as 2008 that they have never made good on. Several affiliates have also reported that PJN has been bouncing payment checks recently. I left PJN back in 2009 and would say affiliates need to exercise caution when using PJN.
I am surprised about what happened to you. What was the main reason for this to happen? And who was the damn advertiser that didn't pay PJN?
I have been using pepperjam for a while now and I have never had a sale with them. To be fair I do not work it too hard. I will say that I like them very much. They look really good, and I like their affiliates - they have a lot of them that are well-known brand names. This is great for branding purposes. If you run a banner ad on your blog for Disney Stores, Warner Bros., or the NFL, you get the benefit of accrued credibility just through the association with these partners, so you are building brand equity even if nobody ever clicks on any banners.