Den Networks — Wrong commitment & now not refunding money

Address:

Ghaziabad, Uttar Pradesh, 201014

I'm mayank singh of shipra suncity. I was using spectranet internet services from last 2 yrs. The plan was 2mbps unlimited quarterly rs2740
But the den sales representative informed me that they are also providing a speed of 5mbps unlimited in rs 2580.
I switched to it but now i came to know that after 30gb the speed is 512kbps.
Now i'm trying to cancel the connection and asking them to refund the money as i've paid for 3 months but they are also not refunding the amount. I asked them to deduct the money for 15 days and refund the rest but still they are not doing it.
Kindly let me know what can be done?
My user name is m_120212 & e-mail id is [protected]@gmail.com.
I'm trying to contact them but every time they are saying the account is not been updated in the records.
Kindly help as feeling helpless against a company.