Changing listing options

Hi.
When I started my site at http://www.djconnexion.co.uk I allowed everyone to list for free.
Now I have disabled all free listings, the only option is a one year paid for listing.
What happens to all the people currently on a free listing when it comes up for renewal?
Do they still get an option to list for free, or are they forced into the paid option (obviously they get to chose if they want to continue and pay…).

Thanks.