Partnership Firm rental Issue

Me (let me refer as A) and my partner ( refered as B) have a Partnership firm XYZ which owns a building. Firm is not registered and exists for more than 20 years. A and B also started a Limited Company named XYZ Limited Company and A is no more on Board of Directors of this XYZ Limited Company, how ever has minority shares( less than 10%). There are other Directors and share holders for XYZ Limited. B is MD and CEO of this XYZ Limited. XYZ Partnership has rented its building to XYZ Limited since 2002, and rent agreement has not been renewed for last 6 years. How ever Company has been paying rent till April 2013. Since then it has stopped paying the rent , however continues to occupy the premisses. Now A and B are not in talking terms and firms account is also kind of frozen due to another issue. Now me (A) what options have to make XYZ Limited to settle the rent dues ? Can I write to XYZ limited to settle the dues on behalf of Firm or should I write as Individual partner ? If the Limited Company does not pay the rent , what options I have to fight alone as partner of firm ?