Society dues

Dear Sir/Madam, I sold my flat in visakhapatnam city and I am presently residing in lucknow city. The flat is situated in a township and is governed by an association which is registered. The new owner bought the flat by completing the registration formalities with full consent. He did not ask for N.O.C. and I also did not provide him with one. There was a storm and some damages to society flats, 2 months before registration of flat. Society decided upon some dues for all flat members. Society bye-laws state that 'if dues are not paid by old owner, they will be collected from new owner'. I was informed about the dues not by society, but by the new owner, four months after sale of the flat. This is because the society tried to collect the dues from the new owner as per their bye-laws. This amount is 15000/- .The new owner does not want to pay this amount. He sent a legal notice to association, threatening them and sent a normal notice to me. The association got scared and is now requesting me to pay the money. The highlights I would like to point out is that the bye laws of the association are in my favour and the new owner went through every detail (except N.O.C) and bought the flat with full consent. Kindly advise what I am supposed to do in this case.