Airtel
Sending bills even after the connection is terminated

I had this Airtel broadband connection which i terminated on 28th June.

These foolish people are still sending me the utility bills!!!

I've already informed them a number of times that my broadband is no longer in use... but they do not pay a heed. I gave this in written to their representative who come to disconnect the connection, I am not using this connection any more. Moreover, the landline phone is also disconnected.

I don't understand, how come i am still getting the bills???

What am i supposed to do in such a case. Please Suggest