'Language' attribute resetting to blank so won't let me complete any listings

I am trying to make my first two listings for unique physical printed books that aren't already on Amazon, they are my IP and I'm the manufacturer, publisher and author.

Every time I try and make a listing they go into inomplete listings / 'fix your products' with the issue description: There is no record of the SKU corresponding to this update on your account. This commonly occurs when there are other issues on your SKU.

When I click on 'edit draft' the language that I had set to 'English' is outlined in red and blank. No matter how many times I list or edit, the language attribute always resets to blank.

I have cleared my cache, updated my browsers, used different browsers (all from Amazon's supported browsers list), used different computers both Mac and PC and nothing has changed.

It has been weeks and I've still had no resolution from seller support, I just keep going around and around, I keep getting the most random suggestions that indicate to me that Amazon has no idea how to fix this and they won't escalate my case to someone who will either fix it, or tell me that they understand what the problem is but they can't fix it.

I've been asked to clear cache etc., but I've also been told that the item names are missing (Not true, you can clearly see the titles in the screenshots that had been sent with the previous message so this was really random and unhelpful, when I pointed out that they do have titles and asked if they can't see the titles on their end my question was ignored), had a message all in Chinese for no apparent reason and been given instructions that I can't follow because I'm an individual seller and the instructions were for functions only available for professional sellers, when I pointed out I need instructions for my account type I was just sent links to informatio about the difference between accounts. Literally not a single question I;ve ever asked support has been acknowledged or answered.

It seems clear to me that there is a bug on Amazon's side, which is not good because it's starting to look like they just will not fix it. I've already spent money on ISBNs and barcodes and I've followed all the instructions, as far as I can see I've done everything right but I still can't list my books.

It's been months now with no movement forward and no escalation to anyone who will answer my questions and it's getting really upsetting, those two books together took me SIX YEARS to draw and write, this is no minor project, it's my life's work. Does anyone have any advice or help for me please?