Property tax arrears with flat sale

Hello Everyone, I have a question for which your advice is needed. I recently sold a flat in Thane where property tax were in arrears since our name and property records were never registered in the property tax. During the course of selling flat, we had appointed a broker who helped with the flat sale and also agreed to help us solve property tax issue for which I duly deposited necessary amount with the broker. The broker submitted application on behalf of the buyer in however since then nothing has moved forward. Now the buyer is threatening me with legal consequences and asking me to shell out more money and expecting me to help. What is the remedy I have in this case if I am served with a legal notice and a police complaint is made as it is not my fault as money was paid immediately to resolve this case