Email is unrealiable. Sites been down alot. (Wooo! Twins win!) Email is unreliable. Did I mention that email is unreliable?
Although I suspect that your email problems are something out of the ordinary, I think it should be pointed out that yes, Internet mail is
unreliable, by design.
And thanks to spam and spam-fighting, it's even less reliable than it was ten years ago.
Still, we're being spoilt by a normal email delivery time of just a few seconds, and feel that something is wrong if it takes more than a couple of minutes.
What guarantees you had with email delivery before, was basically this:
Either your message gets delivered, in which case you'll get no confirmation; or it will not be delivered, in which case you'll get a return message saying that there was a "permanent delivery failure". Some systems gave you a "temporary delivery failure" warning message if email took more than 4 or 8 hours to deliver, and another one if it hadn't reached the recipient system within a day. Failure to deliver within a few days would generate the "permanent delivery failure" message back to the sender.
Well, provided that the sender's email system was working, that is.
In any case, I hope you'll see your problems resolved, whatever they are technically speaking.