Delaware Clinical & Laboratory Physicians

During this year I have had cancer related surgeries I received an alert from Credit Karma that I had a collection item reported to the credit bureau though A-Collections The bill was from Delaware Clinical Labs I have never received a bill from them I have never received a call or message from them I have never received any correspondence from A-Collections where they sent to bill for collections If I would have received a bill it would have been paid How is it that a business can submit something to collection when they never sent a bill? I do not have an account number as a reference as I never received an bill I do not know what the date of the transaction was as I had surgeries this year