Clearly it's not fitness-related. From what you've said, it sounds like the wetsuit either doesn't fit or you didn't put it on properly. When you put it on, you've really got to work on pulling it up as far as it will go, working the neoprene up to the shoulders. Otherwise it'll be too tight around the shoulders so your arms tire very quickly as they're having to stretch the neoprene every stoke.
Maybe their system generates a reference number every time someone starts the online application process, but doesn't free up the number if the application bombs out for some reason? So there's lots of unused numbers.