internet providers

Romola, I've already started sending emails to my contacts letting them know my new number, but it really isn't good enough. The fact that they ask if you want to keep your number, then don't even tell you it's been changed. My daughter tried to phone me, but message said the number wasn't recognised...

This is shocking. I too changed my internet provider.
Initially I thought I wouldn't keep my "landline" telephone, now in fact run on the internet. But a week later I changed my mind and asked to have it back. I specially asked for the original number and it hadn't been reallocated so I got it back.
I'm a widow and live alone, so I realised that if anything happened to my mobile phone (stolen, broken, left on the train) I'd have no way of contacting anyone. It costs a few pounds every month, but I might need it.
Pably15, get back to you new provider and insist that they check to see if your old number is still available.