My medical provider sent a refund of $84.00 to my insurance company (that they requested because they made a mistake and I never knew anything about) and never sent me a bill before sending it to collections. Can they do that by law?
No they cannot. Send the collection company a letter stating that you do not owe the bill. Tell them that there was never a bill sent to you. They will have to verify the amount owed and get proof of the debt. Tell me what happens after that.