Same thing happened to me. I called in the first time, since I was under contract, they had to override for an early upgrade, but could only offer $199. They wouldn't budge in lowering it to $99. So I declined and called again.
The second time, the next rep declined even doing the override, stating that I already called and was "declined an override for the $99 deal". He read it as a decline to override in general, so now I can't even get the $199 price!
It sounds like this may happen to you too, so be cautious...