From a moral standpoint, you should repay what you borrowed. Once the pdls realize they cannot debit your checking account, they will contact you. If you still owe principal, inform them you will repay only what you borrowed
on your terms. If you've overpaid, then request a refund. Let them know you will be filing a complaint, etc. etc. and per info on this website.
An illegal lender will not take you to court. They will, however, turn it over to a collection agency or so-called attorney. If that happens, just request debt verification and after receiving, tell them the same thing.
Good luck. You will eventually prevail.