Referee not responding?

Hello folks!
Recently Croatia issued a new commemorative coin and I tried to contact numista referee for Croatia for adding that new coin. He is not responding after a week. I understand that people don't have time for this and there are a lot of other things to do. After that I tried adding the coin myself and the same referee must approve that but he is absent.
Now my question is: what to do if there is only one referee that is not responding? Is there any other way that I can add my coin to collection?

P. S. I understand that people have jobs, families etc. I also have and I know how that goes. Of course I can wait until coin is added but what if the referee never comes back? I hope that doesn't happen because he is one great contributor to this site.

Keep calm, there's always a master referee who can help out. Usually when the request is pending for 10 days or so, I'm able to process it.

Well, if the referee just disappears from the site (it happened in the past) it will became known exactly in these cases. As Druzhynets said, one of master referees can solve his/her requests in the meantime, which solves the problem momentarily.

If the referee is absent for longer time period, we will just remove him/her from their posts and try to find someone else. With small catalogues with minimum requests, there is a chance we won't find out that referee is missing until regular referee questionaire.