Bill Payment Processed

I paid my bill with more than enough in my account. Everything went as usual, and it said payment processed. I got all of the confirmations as usual (text, email and AT&T account) and wallah, done. This is what I do every month. Nothing was different.

A few days later, I received an email saying I was late, which it had been by a few days, but I had paid it and the late fee and have proof. So I went to my bank account and can see it was taken out on that date. Only... It took $5... Not the rest for some reason. I am beyond confused and now do not have enough to pay the full amount as I paid another bill thinking that priority phone bill had already gone through.
I don't understand what happened. Why did it charge almost nothing? Perhaps just the late fee. I did everything Exactly as I usually do.