Mts — Asking payment without Speed

Address:

Ghaziabad, Uttar Pradesh

I purchased a MTS Mblaze connection 10.10.2012 with a promise of 3.1 Mbps download speed and I paid them for 3 months in advance. After going through the service they give me the speed of 200-300 Kbps only. I complaint about this several times but they promised all the time that they are increasing and make fake promises all the time. At last they send their service engineer on 1.03.2013 and he confirm that I'm right. after quitting from there service they demand me another 2 months rent without adjusting any amount. Is any ISP can claim amount without giving service? Please let me know.