Think it would be a bad business model to block for inactivity. I have an agency who I am prescreened with but have yet to see one of their ladies due to availability not matching and I can still inquire okay a year later.

of them blocking anyone for low volume, but they will make you a low priority if the girl you want is popular and in demand.  Sometimes they will also delete your info if you're inactive for an extended period, so if you come back, you are essentially starting over with them.  I had this happen last month in San Francisco.  It was nearly a year since the last time I was there, so I had to get re-verified.

Like CDL said, I can understand having to be rescreened after a lengthy period of inactivity, but you used the word "block" so I am guessing that you have reached out to this agency and getting crickets in return.  

 
I am only guessing, but if I am guessing correctly and you they are intentionally ignoring you, it's possible that you ended up on a BL somewhere and that's why they aren't getting back to you. BL's have been widely abused and it's quite possible that some girl got her nose out of joint and put you on a BL.

 
One other possibility after a quick look at your reviews, you gave a 6-6 to an agency girl a few months back, Maybe "Mike" didn't take it well and you are now "persona non grata" at his agency. If his is the agency that is "blocking" you, I think we have found the answer to your question.

Blocked, I doubt it, but if you are out of site out of mind...any PIN number or the like you may have received for faster screening may not be honored if you just started contacting them after a period of 4-6 months.

on their site, and lapses clients who haven't used their services.