Validation is a pointless step at this point because the debt is valid. All it will do is throw a temporary delay into things.
What your insurer should have paid or not is immaterial to the medical provider.
"Disputing" things with a collections agency doesn't change anything. They're not really much obliged to do anything other than verifying YOU are the one that the debt is about. They're not obliged to not report things that you are disputing. If you believe things are in error on your credit report you have to dispute it with the credit reporting agency.
They can charge whatever interest was in the original contract with the provider.
What makes you think this is bad faith?
What on earth is consumer court?
The issue would appear to be with your insurer/employer. Why is it the provider's fault YOU racked up medical expenses that didn't get paid?

