They also refused to provide services unless he paid back-pay, up front. That, my friend, is extortion. Done by any other group, they'd call it by it's name.
Refusing to provide services that haven't been paid for is extortion?
For which other group would this be called extortion? Doctors?
They demanded he pay for all the time he had not been protected. That would be like a doctor demanding payment for all the time you were not insured.
You cannot wait until your house is on fire, or wait until you are sick, or wait until you have had a car accident, and then try to buy "insurance" against it for only the interval you are needing service.
Either you pay the full cost of fire protection, or you pay the full cost of your medical procedure, or you pay the full cost of property damage, or you subscribe to an insurance plan. I don't see how this is extortion, or how it is wrong.
But did they ask for payment after rendering services? No, they asked for back insurance
rendering services.