To close the loop on this, I had to email GB a second time after they never responded to my first inquiry. They wrote back to tell my I'd have my refund on Jan 5 - but when I checked my credit card I saw it had hit on Dec 28. About six weeks from time of purchase to refund and the website status never updated throughout the process - it went straight from customs validation needed to refund has been issued successfully. I think this actually worked slightly in my favor as the Euro has strengthened slightly against the dollar since I made my purchases and I got back a bit more than I was expecting
Still waiting on my Planet Payment refund, although the website says the form has been successfully received.