If your base is missing data, asking yourself the following questions may help in finding out how to retrieve your data.
It's entirely possible that your data is still in your base, but just temporarily hidden by filters or in hidden fields.
You may have some filters which are hiding the data you're looking for. If you click on the filters section of the view bar, you can see if filters have been applied.
It is also possible that some of your fields have been hidden. If you click on the filters section of the view bar, you can see in detail which fields have been hidden in the view that you're in.
If you are working with other collaborators who have editor or creator permissions, it is possible that one of them might have deleted the data. Please contact your fellow collaborators and ask if they might have deleted the data.
If your data has definitely been deleted (and not just hidden through view configuration options), you may be able to recover it by restoring one of your base snapshots. For further information on how to restore a base snapshot, please read this article. Please note that workspaces on paid plans have a longer snapshot history.