Back in the bad old days, when you sent an email somewhere containing some vital, time sensitive information, you just assumed that it got there, and that it would not 'conveniently' get lost or delayed somewhere along the line.
Yes, you laugh, but it's true.
When you sent a registered or notarized letter through either the mail or a courier service, you only certified the damn envelope, and not what was in it. Back in the day, you could send someone a contract to sign, and they could send it back to you with a crucial page missing, and claim that that page in question was not included in the original document. And then you might find yourself in a good old-fashioned mess.
For you, that day might have been today. But, at the risk of sounding like a corny advert, maybe tomorrow will be different.