proceedures to protect fractional hotel condo ownership

I bought fractions of hotel condos in Cofresi and Juan Dolio. I have been given "Trust Certificates" as evidence of my ownership in these units. I was hoping that someone would have information on how I can know for sure if these trust certificates are valid? Is there a governmental agency I can go to and verify the authenticity of the certificate? I heard something about the "registrar of titles" in the D.R. I just want to do everything I can to protect my interests, as it appears that the developers may be less than solid at this time. (The hotel condos in Cofresi are up & running & are beautiful, but I understand the one in Juan Dolio, which was supposed to open early 2007 is not even being worked on currently)....any help would be appreciated.