Did you call them? According to the the credit card agreement, depending on method of payment, it can take up to 5 days or longer to credit (they reserve the right to withhold the credit availability).
I am so sorry for the worry this has caused you. If you give us a call at 1-800-531-8722 a member service representative can check on your payment and give you additional details. Hope your trip out of town goes well. Thank you for posting.
I would give USAA a call and ask when funds will be available. In my case, payments from my USAA accounts to my USAA credit cards post the same day, and also reflect on my available credit. I have never had an issue with a payment not posting, or it not immedietely reflecting on my available credit limit. SInce you made the payment from a USAA account, I am sure a quick call will sort it all out.
I am sorry you did not get more detailed information when you called. If you would like more details and wish to speak with someone different please send us a message here with the details you provided above and we will be in touch. Thank you.