Poor internet connection

I use reliance 3G dongle and for the last 2 weeks i have been getting very slow internet connection.I had rechareged 2 weeks back with rs 797.So i called up their customer care about 6 times and lodged complain about 4 times.Despite assuring me that my problem will be resolved , the problem has not been fixed yet.IThe speed is restricted to a maximum of 140 kbps.Being a student of computer science i need to use the net frequently.It is creating a lot of inconvenience.But they are not doing anything in spite of repeated complaints