misleading n internet postpaid connection

Location/place: mysore,karnataka

Name of company/service: MTS india ltd

The MTS sales team offered me the postpaid internet connection in 799 plan,
with following features
1)unlimited download plan.
2)till 6GB the download speed is 3.1MPBS, which i never get.
3)after 6GB usage, i suppose to get 256 KBPS speed. but the i am getting only 12 kbps downloading speed.
4)when i call to customer care., then are saying that, u will get only 144 kpbs which is not informed me early while buying this plan.
5)and MTS is not having a good customer care support .they use very harsh way to answer the calls
6)MTS is not having a toll free number for customer care support .