Of bills and deadlines

So I'm pretty good about making sure the bills stay paid. I pay my phone bill on the fourth of every month because for whatever reason that seems easy for me to remember. I have an electricity bill now that I try to pay after my second paycheck though I still haven't fixed a date for that. I have an automatic payment set up for my car the day after my second paycheck. And this month, my student loan, my biggest, baddest concern, may or may not have gotten away from me. You may ask, how did this happen?
I'll tell you.
So, it was about the eighteenth of this month that I tried to pay my student loan online. I hadn't had to do that in a while. Usually I pay via money order or check- more frequently by check these days. But in a fit of stupidity, I had packed my checks and mailed them in one of the boxes to my parents' house. Ooops. And my mailing address had still not quite caught up with me. So there I was, without my checks. I tried to pay online. I submitted all the information correctly, I thought and called it good.
Then today, on a whim, I checked my bank account balance. It said I had a lot of money. This was both surprising and alarming, because the vast sum of money I had in it, I had already designated for paying off my student loan this month, and in fact had thought I succeeded in that. I called them today, at quarter to five and asked if the payment had in fact gone through and they told me... drumroll... No. It hadn't. Something about the account number being wrong.
But had they told me or notified me in any way? No.
I was just going to proceed under the assumption that all was well until I got an angry letter from them, apparently. Good thing I checked today, and not at minute too soon.
I got back into my account and tried desperately to right things. I resubmitted a vast sum of money to them and got a screen telling me that my payement would be processed as paid today since it wasn't five yet, but as I now know from my previous experience that could be totally useless if I have mistyped a number or have some kind of incorrect account info.
ARGH!
Why didn't they notify me?! Why?!
You know what? The important thing is now I know that doesn't work. And I've learned- if I have a suspiciously large amount of money in the bank for too long, something has probably gone wrong and I should see to it.
Even if the worst happens and I get in trouble for paying this stupid thing late, I have learned a valuable, painful, costly lesson. Even if I don't get dinged for cash, this is playing merry hell with my nerves. I don't know how I'm going to eat that delicious dinner I smell cooking right now. Argh... Frustration.
Fear.
Unhappiness.