Unable to close my seller account

Has anyone else managed to do this? I used their “tool” (https://sellercentral.amazon.co.uk/help/hub/solution/DA_CloseAccount2) but it just sends me in a loop where they send an automated message to my e-mail telling me to use the tool, then close my case without doing anything else.
I have tried 6 or 7 times now, the tool does not work!!