I'm a little surprised at this rate of subscription termination. I've been under the impression PTCL's ADSL service has been reasonably capable, with the exception of their tech support. This impression includes my personal experience with them, having been a subscriber since their launch.
I'm quite certain this rate of deactivation has to do with their piss poor tech support. Getting ADSL installed is a pain, getting assistance for any problems that arise just as bad. The service when working is very good in my opinion. I wish they'd use their heads and try to fix issues that exist on their side, rather than have us pay more to increase returns.
What fraction of the internet bill is the internet line rent? eg I pay Rs5000 for a 2mbps connection, + the line rent for the line itself, which I think is less than Rs.200. Is this the fraction that is being expanded to 450% of its original value? Or is the internet line rent a specific fraction of the Rs.5000 I pay for the bandwidth?
Btw, the first impression I got from the OP was that the rate at which internet bandwidth is sold to other ISPs was being increased 450%. Yes, it made it seem like PTCL sells bandwidth to these ISPs, who in turn package it up for customers. If this is true, a 450% hike in internet prices for other ISPs would be truly diabolical.
EDIT:
I did some googling and it turns out my initial impression was indeed correct. The word "leased" gave it away, since its a term not generally used with the end consumer.
The local leased line is the line PTCL leases to other ISPs, so they can deliver internet to their customers. An increase in the charges of these leased lines will force ISPs other than PTCL to raise their prices. The eventual goal is obvious: people will start shifting to PTCL. Yes, this does mean that PTCLs charges will remain unaffected.
This is a very monopolistic approach. A move like this that unfairly kills off competition is always, in the long run, bad for end consumers. While PTCLs current charges will not increase, a lack of rivals will kill off further growth. If this move does go through, expect PTCL packages to remain unchanged for a long, long time.