Since the voice over the internet servers are not the same as the web servers, such observations are only good for checking basic connectivity.
Check this out -> If you are paying for a service, follow the money to where it goes. Then voice your complaint there.
In the case of most voice over internet users, they don't pay so how could any quality be a sure thing? And why should such a service continue? That is, they can stop at any time for any reason such as a software upgrade or a server in the cloud restarting.
It's not like a land line.