You put them into a Get Them Back bucket and re-market to them with a dedicated program.
Customers are often not gone forever. Yes, it’s really tough to lose them. But they may come back if they have a bad experience with a competitor. Or if other things change.
Put them in a dedicated marketing bucket for Reacquisition. They’ll need special webinars, content, and offers focused on ex-customers.
It’s worth it if you are going long.