Question About PMs

I sent someone a PM sometime last week. Because I'd emailed them the same question yesterday I think, I deleted it. How come they were still able to read it?
What I mean is, when I send PMs, I always ask for a confirm thing so I know that they've read them and I ticked the box and deleted it.

What I mean is, when I send PMs, I always ask for a confirm thing so I know that they've read them and I ticked the box and deleted it.
Comments
- Spam
- Unkind
- Report
0 ·- Spam
- Unkind
- Report
0 ·- Spam
- Unkind
- Report
0 ·- Spam
- Unkind
- Report
0 ·- Spam
- Unkind
- Report
0 ·