In your fact situation, the landlord is obviously a party defendant for making an improper claim in excess of your security deposit as determined by the WI Consumer Protection. If the collection agency that the landord turned over his claim about you and the former rental is still pestering you about it and if it show up on your credit report, then you need to name the collections agency who is pursuing this bill as the agent for the landlord also as a defendant in the intended small claims action.When you show up to court, make sure that you have someone from the WI Consumer Protection to testify on your behalf concerning its determination that the landlord was not complaint with WI statutes with respect to your security deposit.Good luck.