Yes, the feature was available on request (opt-in) with a clear note that it will be in a higher billing tier. But yes, it was in this state (complimentary until further notice) for quite a while, so I totally understand that you got used to it being available 
As we announced in November 2025, these opt-in features where now finally assigned to the respective plans and set into effect mid-march 2026.
That said, our Sales team will contact you - I’m sure you’ll find a solution.
By the way, even without having access to this feature, assigning roles to users should not be broken, you can just not change roles on a project level any more, i.e. you can only assign a user a specific role for all projects. Existing project-specific permissions will remain intact until you change them.
Best regards,
Alex