I see you updated your post after I posted.
If you paid for the Monday email AND the Monday email was deducted from your three, no that does not make sense. Either it's charged as an overage from Week 1, or it counts toward your 3 in Week 2, I don't see how it could be both, but we're clearly missing some information, I think it'll be a matter of getting it clarified with her.

P.S. We were posting at the same time, so I didn't see your latest til I posted, but yes, I think if she's charging, she needs to detail the charges, note what each $10 was for and clarify when the week starts.