Chasing Down Unpaid Invoices for LVP Jobs - What's Your Go-To Method?

Been in flooring for 15 years now, and collections still suck sometimes. Last week I wrapped up a big install of Coretec luxury vinyl plank in this old ranch house, everything looked perfect, customer even complimented the click-lock system. But now it's been 45 days and they're dodging my calls on the final payment. I use QuickBooks for invoicing, but the reminders aren't cutting it anymore. Switched to a stricter terms policy last year, net 15 only, but these homeowners act like it's optional. Anyone got tips on escalating without burning bridges? I hate small claims, but might have to if this drags on.

Man, I feel your pain, had a similar runaround on a hardwood job last month, same ghosting after the walkthrough.