Goodness me, that is awful. I hope you have recovered from the shock!!!!!!!!!!!!!!

It must have been awful. You should get proper care from the nhs and not be threatened with mega bills or fiobbed off with substandard treatment. It just isnt good enough.
I must admit though I have had horrendous experiences with nhs dentists, when my 10 year old chipped his tooth and needed root canal treatment, and he had an extremely painful abcess, I could not find any dentist to give him free nhs treatment. I ended up at the dental hospital. It was a truly traumatic experience. It made me so mad. We just did not have the hundreds of pounds to pay privartely the time. It was an experience my poor son will never forget.
Anyway, I hope you get your situation resolved satisfactorily.
Deb x