Unfounded harassment and non payment of deposit

Undoubtedly the worst property rental agent I have ever had to deal with. Our problems started from before we even moved in to the property. Following the end of our lease they could not reconcile their accounts correctly, issuing a final demand to us for monies NOT owing to them, and then despite confirming that we are in fact in credit, will not pay back the monies owing to us until the landlord confirms it is ok to do so. It is 8 months after our lease came to an end!!! Will be taking this to the EAAB and RHT, as well as considering our own legal action.