Bharat Sanchar Nigam [BSNL] — Possible fraud by BSNL representative

Address:

Delhi

I have been cheated by one of your representatives by BSNL. Here is the series of events :

I called in the following number([protected]) which is listed in Google as the fiber Optic connection (Screenshots attached below). The representative asked me to communicate in whats app.
I inquired the price for a new connection, which he shared as 4500 INR, which he later explained on call that this would include all costs including setup, new routers and accessories etc.
Once the payment is made, he responded back stating that I need to make a payment of additional 2500.

Now when questioned, they are neither ready to refund the amount nor ready to do the installation unless an additional 2500 is paid. They are just forcing me to make additional payment of INR 2500.
They are also not responding in whatsapp or mail and not picking up my call. Proof of all conversation can be provided.