https://scratch.mit.edu/projects/537867195/ look here scratch team

Your suggestion or variations of it has been considered by the Scratch Team and rejected for the following reasons:

The Official List of Rejected Suggestions wrote:

2.1 Adding users to work on projects
Having multiple Scratchers work on the same project would be difficult to moderate not only due to technological limitations but also because it could lead to private messaging; for more information, see #7.1 on this list. This suggestion includes live editing (similar to Google Docs) and other forms of private collaboration. If you would like to work on a project with another Scratcher, you can remix each others' projects.

At the moment, a turn-based collaboration system for shared projects is NOT rejected; you can discuss it on this topic.

Your suggestion or variations of it has been considered by the Scratch Team and rejected for the following reasons:

The Official List of Rejected Suggestions wrote:

7.1 Private messaging
Scratch currently has public messaging, meaning anyone can see the comments that you write. As a result, people are more likely to be respectful since anyone can see the comment. However, with private messaging, people know that only the intended recipient can see the message, which could lead to many more disrespectful or inappropriate comments. The Scratch Team also simply does not have the resources to moderate a private messaging system, precisely because there would be a lot of bad comments. In addition, it is a huge Internet safety concern and is not the purpose of Scratch anyway.

This suggestion extends to allowing users to post links to other private messaging websites, such as Discord. Many such messaging websites are not as well-moderated as Scratch is. If such links were allowed, Scratch may be held responsible if anything bad happens to someone.

I do also belive that voice mails are not easy to moderate and may fall being rejected.

Please take a look at here.