Changing email adress doesn't work

Hi, 

I only want to change my emailadress, but when I want to try I got the following message:
“Cannot update email - "-TlaOfMJzVdfPFeCsF1iADMThi4UPDoyADsS6ZvFbE4" is already taken”

So I know,  the new emailadress already exists (used for an other account in Figma), so I tried to delete that account (got no files in there), but when I want to delete that one, I got the following message “An error occurred while attempting to delete your account.”

I can’t get out of this loophole, and don’t have any other options. What am I doing wrong? 
I already erased my cookies/cache and that kind of stuff.

Thanks in advance! 
Martijn