Detecting trial and/or frozen users

Shopify Partner
4 0 1

We're a Shopify partner app and we're having some issues with people on trial accounts.  Basically, they seem to be creating trial accounts in Shopify, using the Shopify billing to use our app, then using our app until their Shopify account gets frozen.  This means they're using our app but we're not getting paid.  In theory, people could do the same thing with credit card disputes but the barrier there is high enough that it's very rare.

I'm very curious to know what people are doing in this situation and what the recommended approach by Shopify is.  Is there any way in the API to tell if an account is on a Shopify trial?