Say you're open to any cancelled appointments provided there's a few hours notice? You bet folks cancel and you could be squished in sooner! Eval Consultations take longer than regular office visits? But if one is cancelled? YOU ARE LIKELY IN! Just prepare to stop and change directions in life for that cancellation! AND don't ever ASK why that someone else cancelled.
Your initial GP should be apologetic! AND he should work his *ss off to make up for such a mistake. Ask for and request a copy of what he's sent to that insurance company to correct that issue? Or it could become a problem for life regarding disability in the future-His[docs'] mistake, unless you have proof that it's had attempts to be corrected, are not good things to have in files!
Good luck! Keep faith that it's likely something 'simple' - I hope and pray that it is! 's - j