Kudos to Webshots
A while ago we were having trouble with Webshots.com: some images downloaded correctly, many stalled. Customer service was prompt, and we interacted a bit, including lots of technical questions and information they asked us. In the end they determined it was a bug in how the app interacted with IE. Worked fine with FireFox which gave us a workaround.
So although they didn’t resolve the issue, they convinced me that they were serious about diagnosis and solving the issue in the future.