Credit where it's due. Being a total cheapskate I'm always happy to grab a bargain. EF sold me a Windows 10 Pro key for a stupidly low price. However, when I tried to register it returned an error. I attempted to resolve the issue for a little while but it became apparent the code was never going to work. I emailed EF support with my issue and a screenshot. Within 4 minutes I had received a reply offering a replacement or refund. I requested a replacement and 10 minutes later I had a replacement key that worked perfectly. I've worked in IT for 20 years and this is the fastest resolution I have ever experienced.