One thing to suggest, if you have more than one phone at your disposal, use it also! Several mentioned having very long waits on the line they called in right at 7 on, but when they used a second line to call in, that line would sometimes be answered much faster! Not sure why,

.. but it wouldn't hurt to try, especially since you only have so much time that morning to hold. I dialed in starting 6:59 over and over and over, till it finally rang to their menu, and my call lasted 33 minutes including the time it took to book

...
Fingers crossed that you are able to book in the AM, so you won't have to worry through the day!