wrong plan and misselling

Location/place: kolkata/dumdum

Name of company/service: Arbees Teleservices

I,Souvik Das,7 Mondal Para Lane Dumdum kolkata-700090,hereby informed that I was cheated by TATA Docomo,Arbes Teleservices dealer.I buy a Tata Photon device(no 9230773920) @1200on 16th June 2012.The dealer convinced me that my plan will be 500 unlimited download plan and the speed will be 3.1mbps all the time,It will not decreased at all even in my bill it is clearly mentioned but after the connection confirmed from the 3rd day after buying that device I am not able to log in and my speed is not upto the mark it is just 10 kbps.I repeatedly complained against the company via complain no 314365533 but they didnot bother to entertain me.They are not responding at all.My bill is near about 562,I donot know what to do.Kindly help me.