The number you dialled has not been recognised

I used to have a Doro mobile phone but it no longer works. In any case there is no mobile signal round my house. I have a PayPal account which I can log into, but I cannot use it because they cannot check my identity via the obsolete mobile number given in my account details. PayPal has a Customer Support Contact-Us web page, which gives a telephone number, 1-402-935-2050, but ringing it only elicits “the number you have dialled has not been recognised”. I have never used PayPal anyway, but it seems that lots of websites use PayPal to deal with identity verification. I did find a PayPal webpage where they offered to ring me back. But when they did, the phone simply squawked; I presume that this is because their system is only for mobile phones and not for landlines. So how do I cancel my PayPal account?
Perhaps there are others among the ancientry that resent their increasing isolation. It turns out that without a mobile phone I cannot even park a car or charge it up if it ls electric. Something must be done!

Remember to prefix the number with zero! Or + from a mobile.

But they do have a UK customer service line: 0203 901 7000

Or ever better – Freephone number available from local landline only: 0800 358 7911

Thanks. I actually managed to talk to a human, and have cancelled my account.