Stop Order and MAC on landline in new flat

I've just moved into a new rented flat and attempted to move landline and phone service across from old flat to the new one, however i've been told there is a stop order on the line, and that another ISP has a tag on it so i can't do anything till that expires.
The stop order is for about 3 weeks from now and i work from home several days a week, so need to get the services moved asap.

I know plenty about MAC and switching BB providers etc, however i have no knowledge about Stop orders.
I have had a search and haven't found much useful info on Stop orders.

What exactly are they? Are they disconnection of the line, or just a ceasing of service by that phone provider?

Is there any way to speed up this process, for instance seeing if landlord is able to get details from previous tenant?

If i get only a MAC code from previous tenant, is that enough to be able to change phone + BB provider or do i need the stop order cancelled as well to change both?

cheers Jonathan

It means the previous occupant probably did not tell provider about moving until the day of move, thus taking time to stop their services.

A mac only moves the broadband, does nothing for the telephone, and very likely the person was with a full LLU provider before anyway