Look at the bottom right corner of your screen (or the top right, depending on your UI scale). Click the two-person icon (Friends list).
That’s it. You have unblocked them. This is the most common support ticket. You unblocked them, but in the next game, they are still muted.
Click .
Scroll through the list of everyone you have ever blocked. Valorant does not have a search bar for the blocked list (annoying, we know), so you may have to look closely.