transfer to the new updated site the membership. (the references would be transferred)  
contact them by email

There's another thread on the same subject from a few days ago (see link below).  If you didn't ask to have your account transferred last year when they had both websites active, then you will have to contact DC.  Your old account has not been lost.  Another poster mentioned that they will charge a transfer fee, since the grace period has expired

My multiple requests were ignored

I too paid for lifetime and made several transfer requests during the grace period but they were all ignored.  I refuse be extorted for more money.

For the Past 2 Months

I've been unable to login to my account. No one at Date-Check has ever replied to my numerous login requests. I finally gave up on Date-Check, and only use P411 and TER.

I was able to get my lifetime membership transferred last month, but my references were wiped out. Only a couple of the providers who I've seen are up on the new site anyway.

Starting over with references wouldn't be a big deal if the overall utility of the site is maintained. But that mostly depends on the number of providers who will be using the new site, and at this point things aren't encouraging. Some great ones, but just a small number.  

Date-Check is known for having a large number of inactive provider profiles up, but I'm surprised they didn't do more to make sure more of the active ones got transferred.  

I figure I've gotten my money's worth with four years of "lifetime" membership, so there's no point in being outraged. I'll probably end up joining P411 at some point unless Date-Check gets its act together.

And whenever I've attempted to contact customer service, I don't get a response.

It's whatever. The interface on that site burned my retinas.