What do you mean 'BT say my line is done' If you mean the exchange is MaxDSL enabled, that does not mean your line has been speed upgraded. PN still have to place an order for MaxDSL for your line.
The upgrades to MaxDSL are not being done on your billing date as PN can't do that many each day. PN are submitting regrade orders at a rate of about 700 / day (this is a BT limit imposed on PN and all other ISPs) which means some will have to wait many months before they are upgraded.
There are many threads discussing this subjet where your Q has been answered. May I suggest you read through those threads where other questions you may have will also have been answered.