My line should have been switched from BT to the post office today.
How can I find out if it actually has changed?
My broadband should have switched also but as yet I have not received my router & my old ISP is still working

What happens when you dial 150 / 151?

Once you add in the cost of Caller Display and not being able to use Call 18185, using the PO, you end up paying more.

With a BT line, calls automatically through Primus and other calls through 18185 and BT, you can save some decent money.