I used to promote them once upon a time and they paid me on time with no hassles.
The only thing I would watch for is that they close your account if you go for a period without sending any players as happened to me. I found that a bit odd actually but there you go. Well that was what they said – it may be because I removed their links and posted publically my thoughts on the Spam issue last year. Who knows 
Silly question maybe, and not meant to be offensive, but 888 were showing signs of attempting to clear up affiliate search engine spam…is it possible they tagged you as offending in this area? That might explain the issue.