Sometimes it helps to bitch.

The restriction on our PayPal account has been lifted. We didn't do anything else. I got a message from someone there who read my post and apologized and said he'd see if there was anything he could do (though that wasn't his area). Not sure if that's what did it or not (if so, thank you, thank you, thank you!), but it was good to at least hear from someone there who cared. The bright side of all this annoyance was that it prompted me to set up our own credit-card taking system, something I've been meaning to do anyway. There are higher risks to doing so, and we're still using PayPal for some things. We'll see how it goes.