I had a similar situation with Spirit and it did not end well. They weren't willing to work with me AT ALL. I'm sure it has a lot to do with who you get on the phone and whether they're feeling nice that day. In my case, it was so frustrating b/c their customer service is clearly outsourced and I could barely have a conversation with the rep...couldn't understand what he was saying. I asked to be transferred to a supervisor and the guy was a TOTAL jerk.

I hung up and called again--same runaround. I hope you have better luck. As for me, I will not fly with them again. Now that Southwest has lots of flights out of Milwaukee, I'm sticking with them.
Also, that's a great rate you got with Thrifty! We're going 12/1-12/4 and I have yet to find a good rate, other than Advantage. I got a midsize for the week for $133 including taxes/fees from Advantage but I'm afraid to use them due to the really awful reviews.