mtnl modem sucks

hi guys by luck i got connected and u are my last hope! mtnl ain't bothered about consumers .they even dont take call at customer care.

I have ADSL 2 UT-304R2 modem.
the problem is that it gets connected for sometime and then gets disconnected after a minute or so & then gets connected again .....
the xDSL light is blinking or off meaning a poor connection...I tried reconfiguring my modem but no avail.WTF help me out plz