Well, I am finally making progress. I filled in the support form on their website and was contacted by someone asking for more details. I responded with the requested information. Today the scheduler finally got back to me. She sent a screenshot of the error from paypal. They had used an ancient email that I used when I first did some assignments for them. It's strange, since for the last several years they have been sending my payments to another email. As soon as I stopped using the old address, I informed the scheduler I dealt with at the time that I was not using that address anymore and let her know the new address to use. I don't know how that old address popped up after several years.
So, I just wrote to the scheduler and told her what the problem was. I told her that, from my understanding, is that they would need to reclaim the payment and then send it to the correct email. Hopefully they will do that soon. It is annoying, though, because weeks ago I asked her if she could please confirm what email address the payment had been sent to, but she never got back to me. Had she responded, this would have all been resolved much more quickly.