Do I need a landlord tenant attorney?

Hello, We moved out of our rented apartment end of Dec 2012. We just found out 3 years later that the landlord had filed a petition in landlord-tenant court for non payment. They claim we did not pay Nov and Dec 2012 rent and had served us with a rent demand by both registered mail and in person delivery. However, the landlord did not take any further action because they received the rent money in Jan 2013. The question is what should we do? Should we file for a discontinuance with prejudice? Is there anyway to make the petition in court go away? What action can we take to clear our name? We have always paid our rent on time and actually own two apartments now (this petition never showed up in any of those background checks). Please help!