I have had even worse luck with dentists. One went bankrupt owing me $400 (I was noted in his paperwork), and another mysteriously had a credit of $1000 from an overpayment we made that just “disappeared.”
If the providers are participating with your insurance, refuse payment until AFTER billings are run through insurance. My insurance discourages patient payments until accurate patient responsible amounts are determined. Providers that demand upfront payments are told to contact the carrier and can have their contracts voided.