Kindle Vella? You mean that app for serialized short stories? A short story is not a novel. Neither is a blog post.
The Royal family didn't write the books for her. She didn't publish every book she ever wrote. 171 or so were published posthumously, which essentially broke her own previous record of 26. Not sure if Guiness recognizes that though as Google's top websites' info is inconsistent.
Either way, the record has to be measureable and it has to be beatable. If you got declined, you didn't meet the requirements. It's their reputation. You don't get to dictate terms, jeopardizing the prestige of Guiness and all the other record holders just to inflate your own ego.
If it makes you feel any better, being a record holder didn't bring her anywhere near as much money as Danielle Steele.
Looking at their site, the application should have cost you $800, not $1000. If you paid 1k, you applied for a new record, not to break one already established. That may have been why you were rejected. The site also says that for most records that take a long time, like most books published in a year, you have to apply before you begin you attempt so that criteria can be met and independent verification csn be made. If you applied after you wrote your stories based on your own recording, you would have been rejected outright.
Face it. You messed up and you're bitter.