I'm using Mtnl mumbai and hence, not facing this issue.
But I recommend you all to
1. Complain. Don't let them close the ticket when they send a lineman or do something that won't help this issue.
2. Head to the telephone exchange and speak to the SDE who handles broadband. If he/she doesn't understand, ask for a higher up.
Keep asking for a higher up and don't leave. Most people give up very quickly, if you're persistent, MTNL has no choice but to take this up.
Find out how you can meet the CGM. It's your right, don't take no for an answer. If he/she doesn't know about it, ask her/him who handles this and get a contact and then pursue that.
See if all of you can meet up and go together as a team of 10-15. MTNL surely can't ignore you or send you away. Don't ever be rude though, talk nicely but firmly. Worked for me many a times.