My 2 cents:

The patient says the non-Medicare insurance is WC. WC carriers don't normally pay full charges that I am aware of. There is usually a WC fee schedule that normally applies.

The WC carrier also won't pay when it was not a work related injury. You state that there is no injury, only a medical condition. So, to better answer, why did the patient come in to be seen?

I would pend any possible refunds until this can be ironed out as to who has responsibility towards the claim. I don't feel there is a rush to judgement until all questions have been answered.