Do I need two filters to strain cold brew coffee?
I make cold brew regularly using an ISI whipper, and simply filter through one paper filter in a Chemex set up.  So, I am sure you are just fine.  The wool filter appears to be the main filter in this system, with the paper filter in place simply to extend its life (see the FAQ on the website).  You probably want to go back to the wool filter, since this is the design of the product, but I am sure your result is drinkable.