Given the way call centers are all about “production” and getting through the call as fast as possible (and with the fewest complaints if that can be managed), it’s not rude for either of you on that call to do what you do. That is, not rude for her to speak quickly – as long as it’s still accurate and factual speech – nor is it rude of you to say, “I don’t get what you just said.”
Where you might have let things get too far is in waiting for however long it took for her to catch her breath. If you let her speak uninterrupted for, say, two minutes (because she can do that, let’s say), then you just wasted two minutes of your time and hers. It would be understandable if she were miffed that you waited so long out of a misplaced politeness.
On the other hand, the eight-minute wait for a call transfer or new pickup is probably a glitch in the system. She may have attempted a transfer to another operator whom she assumed to be present and available, but who is not, but no one knows you’re still on hold.
When I’m on hold for any length of time in a business call, then I just hang up and call back. Only government offices seem to feel that indefinite and interminable wait time is acceptable to their callers. You’re not being “punished”; the call was dropped, and they’ll apologize profusely – and sincerely – when you call back to notify them. (The benefit of that might be for operators who are leaving their stations to explicitly change their status to “not available” to help prevent those kinds of things.)