collection company reporting incorrect information to the credit bureau. Is there any recourse?

I got a credit alert the other day because a collection agency reported a debt that they bought from my old bank CIBC because i walked away from a checking account when they charged me almost 2K in NSF fees at $45 per transaction. I fought with the bank and made a formal complaint, they offered to reduce it down to $800 because they claimed i was partly at fault. I refused that offer and they sold the debt to a collection agency Gatestone & Co Inc.

Gatestone called in october wanting payment. No paperwork from the bank or collection agency. All I could find was an email in my spambox stating I owe them $1400 from a CIBC loan. Once i figured out what the debt was I told them about my dispute with the bank, the appeal and I said I had 6 months to get the matter to the ombudsman for arbitration. The guy hung up and the robo-calls commenced.

last week they made a report to Equifax and my credit score dropped. They claimed in the report that I have an open loan of $1428 that has a passed due minimum payment of $1501 owing somehow. The report claims that i paid them in November and December but missed January's payment. I haven't paid anything to the bank or collection agency stating clearly to them that I'm disputing the charges.

My question is do I have a recourse if I call the credit bureau Monday morning and point out all these issues? my credit has dropped already and who knows what else they might report since they have an adversion to the truth