Do you have a late payment fee?

ie:
Our memberships are set to bill upon purchase date. Clients can book their classes on a rolling 30 day schedule. (This works for our studio/instructors schedules and not something that we are able to change at this time)
We are running into an issue with 2-3 clients where they are religiously late to pay for their membership but can attend classes if they have them booked prior to their auto bill declining. Their card will decline for 2-3 weeks at a time. I’m wondering if I should put a “account will be frozen after XX days” rule into effect or “$XX amount will be billed” if not paid on time.

Has anyone experienced anything like this?