I assume you've requested for pro support and the pro support have already replied you via sales@gvectors.com email address. Please check your email and spam box. The email has been sent to p....a@gmail.com email address.

1 - Establish the reason why the wipe-out happened?

It seems you've done some database manipulation.

2 - Recover the current Forum which has +2.000 topics?

3 - Avoid this from happening again?

I think the problem is the boardid, your data should not be lost. 

While we review this, we need to :

1 - Establish the reason why the wipe-out happened?

2 - Recover the current Forum which has +2.000 topics?

3 - Avoid this from happening again?

4 - Understand how the Pro Support works, I see no where to contact directly or get in touch apart from this public forum?

Please check the database tables. If you have only one board in wpForo > Boards admin page, you should edit the wp_wpforo_boards table and set the value of boardid as 0. And delete wpForo caches in Dashboard > Overview admin page.

Do not use the wpforo tables with numeric prefixes like wp_2_wpforo.

For the pro support, please go to this page: https://wpforo.com/pro-support/#plugin-support