non-hearing of complaints regarding new connection which has been overtimed which they mentioned

It has been very harassing that there is no hearing and action by IGL regarding new connection of PNG at my residence in sector-11, Rohini.
They claim / provide a time period of 90 days after creation of B.P.Number for a new connection that it would be installed within 90 days of creation of Business Partner number of a consumer. But it has been now more than 135 days after creation of B.P.No.-4000284111 and I have registered many complaints at their customer care number-18601801817 but no supply has been started till date (Reference complaint numbers-PRJ20141656502, PRJ20141699457, PRJ20141702700 and two mails as on date-18 Sep & 20 Sep).
I really want a strict action against such type of company so that they can not do such things with other customers. If they are so over-burdened with their work then why they have opened the connections for that area. Is there some body who can do the needful against such type of company.