Tiscali lose account - now no MAC code - what next?

My sister has been with Tiscali for years and has recently been having enormous problems with line speed having been on a fixed 0.5 Mbps line. The exchange is Chartham (Kent) with no LLU or anything other than DSL Max options. I have managed to get Tiscali to remove the fix and she is on the Max service but with speeds 2-3Mb due to line length and the fact she lives in the styx.

She has not suffered the migration to Talk Talk because they have no records of her account and aren't able to supply a MAC. She ahs been told there have been 1500 accounts lost in this way? Although I am with TT (with no issues at all), I have not encouraged her to sign up to TT as not on LLU. Her dealings with TT have been less than impressive (very unhelpful sales phone reps). She has recently had a letter saying the BB will be turned off 6/5/11.

She wants to go to BT but the line (correctly) still shows BB attached and BT want a MAC which she cannot get.

I have 3 questions:
How long if she lets the BB lapse as per the letter before she can sign with BT?
However, if there are no account details - how do they know to turn the line off?
Can BT forceably remove a flag from the line as it will be on their kit?

As I understand it once you have control of the line (i.e. you are paying the line rental), you can ask your CP to get BTW to remove any flags.
So, in this case I'd move the line rental to BT Retail (no MAC required) to get control of the line. Then I'd wait for the Tiscai BB to be disconnected as advised on 6/5/11. Then I'd contact BT Retail and ask them to sort out the BB (giving them a copy of the TT letter showing that the Tiscali BB as been disconnected if required). And, I'd email / ring them every day until sorted.
Good Luck!

The line rental is already with BT - Tiscali was just separate BB. But we cannot ask CP (assume is current provider) as they now have no records of the account due to Tiscali losing some on way to Talk Talk.

Looking like will just wait until BB has gone 6/5/11 - however, I am not hopeful that the BB will be disconnected, but thanks for replying.

In reply to a post by EViLHomer:

But we cannot ask CP (assume is current provider) as they now have no records of the account due to Tiscali losing some on way to Talk Talk.

Think he means ask BT, her phone provider.

In reply to a post by EViLHomer:

She has recently had a letter saying the BB will be turned off 6/5/11.

Why? Did she ask for the BB to Cease? If so, she can ask for a new BB Provide with any ISP once the Cease has cleared.

Why? Did she ask for the BB to Cease? If so, she can ask for a new BB Provide with any ISP once the Cease has cleared.

No this is the weird thing she didn't, however she has also just discovered that she isn't paying for her BB anyway (since Jan). Quite why they claim to have no details of the account but know to turn it off (not even sure is because of non-payment, but have to assume so).

Anyway only have to wait 2 more days and then hope that the cease has gone through OK.