Late Payments Question

I own a marketing agency and have an organization that is a longtime client of mine (5+ years). This year they changed leadership and the new hire is struggling in some of her duties – one of which is payments to contractors. For months now, I have to follow up 3-5 times on a specific invoice to be paid. She genuinely just seems to be struggling with the accounting part of her job. Recently, I switched her to quarterly payments in an effort to help her have to cut checks less and for me to have less work of continuing following up. That said, checks are still late and I’m back to following up 3-5 times to get paid on an invoice.

I think my compassion for her and enjoyment of this organization/client is getting in the way of taking the right action for my business. Technically, my contracts have a late payment fee clause that I have yet to assess. The main reason I have not added late fees to their invoices are…. they are “good for it” – this is an organization I have no doubt will pay me. It’s just going to be 45-60 days later than I wanted… my company is strong enough to where we don’t NEED the money right then and there.

I’m looking for some business advice here … My model is giving the organization compassion, understanding and ultimately leniency on this I think from a positive place. But the business/accounting side of me says… ok, enough is enough!

Thank you for the help,