“My approved files are missing from my contributor dashboard.”

What country do reside in?

Turkey, Indonesia and Qatar use regional filters. 

Try changing your country in the address bar to Canada, UK, France, or Australia. 

Some perspective... How many assets do you have in total, and how many are missing?

This week I uploaded a batch of similar theme and approved. One sold the next day, but it doesn't show in my contributor feed. When I searched it on Adobestock buyer portal, it shows up on the first page when I enter the asset description I used.

So unless you don't find them there, I would not worry

Surly not. But it may be, that when looking at your public profile, you do not see any of your approved assets. But approved assets are open for sale, and you may even have experienced some sales.

What happens is that you live in a region, where assets need to get an additional vetting before Adobe will put them up for sale in your region. There are a couple of such regions, and I suppose, the additional vetting is needed to ensure that they are in-line with local laws. As there are only 2 regions (restricted and not-restricted) the most severe laws will be applicable. There is nothing you can do about, but be ensured, that I am also restricted with my assets in your region. It is applied to all assets, and it is no disadvantage for you, except if you are producing highly localized assets.