I purchased mine from ImportCDs, and first contacted them to arrange a return, but once I saw (in this thread and elsewhere) wider reports of problems, I assumed a replacement would have the same issues and held on to the set. I then reached out to both Cherry Red and Esoteric to report the problem and ask about replacement discs. I'm not sure which of them acted on my email, but assume they coordinated their response; it was Cherry Red that got back to me and offered the replacements once I sent proof-of-purchase (as mentioned earlier in this thread).
Do you have the details of who you contacted? I would very much appreciate it if you shared that info with us here.