I''d just like to update on my story. As I said, I had contacted support. Although I said I had screenshots to back my claim, they did not ask for any of it. Instead, I got a very polite reply saying this should not have happened, and my entry fee was credited
Although I'm disappointed that I could not move on to claim a bigger prize, this was probably the best I could expect under the circumstances.
So thanks WGTChamp and the WGT team for owning up to the problem and working towards a fix. I liked the format and will give it another try when it comes back.