I look forward to the solution. Cheer up.

But ... are we still without a solution? Did I only use this feature?

ah, I'm not alone.
I didn't see any real confirmation of the problem out there in the well-known FB groups.
Not so happy with this, ran 2 shows without it.
Hope its fixed next Sunday.

Just to add some clarity for those unaware of all of Twitters changes, earlier this year they announced changes to their API which are now going live. These changes include removing the ability for free API access to 'read' tweets which is needed for 3rd party apps such as vMix social or many others to get tweet data and display it in some way.

The updated API pricing can be found here: https://developer.twitter.com/en/products/twitter-api

In short, the free tier just allows posting some tweets. To read tweets for such in vMix social would cost the user $100 per month for reading up to 10,000 tweets. And if vMix was to cover the cost on their end for all users of vMix social they would need to be on the Enterprise tier, which from what people have been reporting the cheapest Enterprise tier starts at $42,000 per month.

The outcome of this is that it would be ludicrously expensive for vMix to use the Enterprise tier so that's not even a sensible option, and the free tier is not usable for reading tweets, so the only remaining option from the way I see it would be for vMix to update vMix Social to allow end users that are willing to pay $100/month to subscribe to that tier and paste their apps credentials into vMix social so that it can use those credentials to make the API requests needed. If vMix was to not update the only remaining choice is to use a non-vMix service for retrieving tweets (which would still require a $100/month fee) and then using that as a data-source.