Association should refuse to transfer flat in its records unless old dues are paid 

2) sue the seller to recover Rs 20000 with interest 

Seller has to pay as he is member of the association in its records 

dont raise bills in name of new member but in name of old member

Serve legal notice to old and new owner regarding the pending maintenace seek maintenace from them. The association needs to send the in case they fails to pay maintennace. 

A recover suit for same needs to be filed.

See if the maintenance is due before selling the seller is responsible for same.

Don't include the new owner as a member of society. He looses all rights as a member. 

2) intitiate recovery proceedings against the new owner under the cooperative societies law applicable in your state

The new buyer is liable to pay the outstanding dues, due to his mistake in not obtaining the NOC from the association with respect to the flat purchased by him. Later on he can file a suit for recovery of money against the previous owner and recover those monies from him along with interest and other incidental charges. 

If the new owner does not respond then the association can take cohesive steps to recover its dues together with interest and other incidentals. 

Issue a legal notice to seller and new buyer file a recovery suit against them. 

Dear Sir,

You get issue legal notice to both and then file a civil suit for recovery.

Hello, 

1)  The buyer needs to pay up as he's in occupation and ought to have got arrears cleared by the earlier owner. 

2)  Send legal notice tho both the current owner and the previous seeking payment. 

1) Don't issue share certificate on New buyer's name and don't allow him any association functions. 

2) Don't allow him to attend the meeting nor election voting in the association.

You don't have to transfer the share certificate in the new owners name till he pays the money. You can recover the amount through recovery proceedings from dy. Registrar

Hi,

You may issue notice to both the buyers to pay the arrears and clear the dues. If not paid, you may initiate recovery proceedings as per bye-laws. 

1. For Recovery of outstanding dues of past /present member, the Association should file Civil Suit for Recovery, on the current occupant of the property, AFTER duly serving legal notice, by following due procedure of law.

2. Association should not transfer membership to the new owner and discontinue certain services (parking, lifting rubbish, swimming pool, gym....)

Keep Smiling .... Hemant Agarwal

1. As per the information mentioned in the present query, makes it clear that the old owner is not at all interested in solving the issue, and new one is refusing to pay the same.
2. The law says that at the time of buying the property, new owner will be responsible for past dues, and he is blind to give the same.
3. If he had not been informed by he old owner then he has his own remedy to reimburse the same, but surely, he cannot say no for paying the past dues.

It is the responsibility of the buyer to find out any dues owed to Association before he buys, because he is liable as per legal view. He can claim that amount from the seller by sending legal notice provided a clause mentioned in your sale agreement give provision. ( Normally we include this clause)

You have to issue notice to the new owner who will put pressure on his vendor to pay the dues.

The association can pressurise the new buyer about payment of  dues to the property to the association and can inform about the drastic action that will be initiated for failing to honor the payment of dues. 

Since the old owner is not visible in the sight and he cannot be approached whereas the dues are still  outstanding agaisnt the proeprty with the association, the association can very well issue a legal demand notice to the new owner about this and put pressure on him.