Unfortunately, it can be blocked by some providers with over-agressive spam filters.
You need to verify your email box because it gives you guarantee that you will get all event notifications, otherwise the service doesn't make sense. So, if you didn't receive an activation email within 24 hours and you have checked Spam/Junk folder in your email account - it's likely that your email provider doesn't like us. In this case we can only apologize and hope that you'll give us a try with another email address.
No, the notification for one event will be sent only once a day, even if the event has several rules that intersect at the same day.
However, if you really need it, you can create copy of the same event and set up different notification time.
As an option, you can add another rule or set up dedicated event that will function as additional notification for the appropriate event.
Yes, you can do it right after account activation or later in Settings area. By default the server uses UTC time.
The limit is 1000 events per one account.