Why do I have to prefix all calls with 1280 when line rental with Plusnet

[#1]

Hi,
I recently transferred my phone calls and line rental to Plusnet and was told everything was activated last Saturday.  However, when I tried to make a phone call all I got was a recorded message "you are not authorized to use this service".    After referring to the Plusnet troubleshooter, I tried prefixing my call with "1280" and I was able to make the connection.
Since both phone calls and line rental are supposedly now with Plusnet, surely I shouldn't have to prefix my all my calls?
By the way, when I called the held line the operator had never heard of the 1280 prefix.

[#2]

Who supplied your line before? 1280 is to route the calls over the BT network which suggest that your line is still with your old supplier.

[#3]

TalkTalk Onetel.

[#4]

now the battle starts, getting off The dreaded TT, first make sure that TT cant take any money. make sure they dont kill you number

[#5]

I have already cancelled my direct debit with Talktalk.    Can't Plusnet sort this easily enough?

[#6]

Another week goes by and as some expected this is proving difficult to sort out.  Plusnet are keeping me updated though, so that's a positive.

[#7]

Quote from: lancasi

as some expected this is proving difficult to sort out.

Anything to do with leaving TT's service is difficult
Now I'm not saying they do it deliberately......................................but