Email Software Resources

On certain occasions, it gets stuck or hangs, and I would like better performance.

Occasionally I find it difficult to find some files that are shared with me, I would like to know that it may be that I have badly configured?

I created an a google spreadsheet, as the owner of the file. I restricted access to this item that was once shared with someone. That person was able to request access. I thought once removed access, no one can be able to see the file. It becomes a harassment and security issue.