Why has my landline number changed?

[#1]

Having just signed up to Plusnet and requested to keep my number, have just received status update to tell me my number has been changed? I don't want a new number, and that is why I chose to keep existing! any advice? 

[#2]

Same thing has happened to me only I didn't get any notification that the number had been changed only found out when someone sent me a Whatsapp message to say my number was unavailable.

[#3]

@GJM09, I'm really sorry to see this, can you send me a PM with your username so I can have a look into it? - Adam