Internet Speed

This complaint is regarding MTNL Mumbai I am a subscriber of the MTNL and using the internet and telephone services from past 10years. Earlier i used to get a decent speed for internet, but from past 3years i am facing a huge problem the earlier plan i had was of 12 mbps and i used get upto 8mbps speed and sometimes reached to 10mbps/ Post that drop it started getting worst i changed my plan to 10mbps and used to get around 4 to 6mbps i complained to mtnl regarding this issue a several times, nothing happened. Finally i shifted to 6mbps plan and now i am getting speed of 1mbps or low with frequent disconnection of internet in every 5 to 10mins. i am paying a lot for the internet which is ok but the speed and connectivity promised is not given. please help me to get refund of money for the services i paid but was not given or provided to me from MTNL