Exactly this. Is what I meant by them working with you. They aren't playing some devilish game of trying to trick you into paying more. They tell you why they say you owe something and what it would take to get them to change that. And are fine if you need time to find it.

If you are actively trying to avoid the calls, I'm sure that is probably not a good idea. But, that is basically in the "actively trying to commit fraud" territory, at that point. No?