Alternative
The only people I communicated with on Skype are old people.... I'm so glad to be finally rid of it. Deleted 11 years of chats today and uninstalled the app. Yayay!
I used VoipStunt https://voipstunt.com for 20 years but they don't issue numbers anymore (I still have my 020 London number).
One client asked me today how he can call landlines (like many others above). I recommended an Australian company to him called Aatrox https://aatroxcommunications.com.au/ - I pay a small monthly fee and get charged almost nothing for calls and I get an Australian number. I then use a Cisco VOIP box and a Panasonic cordless phone. Very nice. You can also just use the MobileVOIP app so no need for hardware. They can get you numbers in many countries. And can't recommend the customer service enough... I had a problem configuring the box and one of their guys called me up, did a screen share and helped me get it working.