The phone number is posted on Avast's support page and use the name Avast therefore they are Avast.
No, that is not how it works. avast is responsible for hiring them and for the taking care that they do a good job, but they aren't part of avast. It is still a separate company.
avast is working on improving things, but that can't be done overnight.
Amongst other things, there are the agreements in contracts that they have to follow.
If it was as simple as just removing the phone number from the website and say to them "screw it", avast would have done so.
As for your condisending attitude I don't appreciate it and it gives me even more reason to not want to use Avast anymore
I'm not working for avast. I was a paid customer and now are only using the free version. With all the current problems I don't feel it is worth spending my money on.