I had a similar situation a short time ago but was resolved the next business day I advised Shippo and they told me they were aware of the problem with labels. It was suggested to wait until the next day. When I refreshed Shippo, I was able to print the required labels with no problem. If this is your situation all good. Because this involves a transaction over a month ago imply to Rebekah in an email that you would like a refund referencing the transaction in question and not a credit because this was a system error at their end. And if you are seeing a late shipment strike you should be able to chat with eBay CS to request any strikes removed explaining what happened.
-Lotz