No Intimation of bill increasing bill amount

Location/place: Mumbai

Name of company/service: Mahanagar Telephone Nigam Limited, MUMBAI

Sir,
My MTNL number is 28066803, CA number is: 2090396963
When i registered for mtnl’s broadband plan, i was told that the bill amount will be 550rs by mtnl (kandivali branch) i opted for monthly 495 broadband plan…
Now suddenly they increased the plan amount to Rs.550 and my bill amount is now Rs.667/-. I called 1504, they said that mtnl has increased the plan to 550 and the speed has also increased to 650kbps, but i get the speed of 54kbps, even though giving written complaints no action has been taken. And the numbers on the mtnl bill never works, and the helpline numbers of 1500, 1504, the customr care pick up the call but never talk, i can hear them talking in background but they never speak, my complaint docket number is 2880.
Please look into this matter, i am middle class person, a small increase in this amount does matter