Urgent support needed for locked Amazon seller account

My Amazon seller account was unexpectedly locked, and Amazon claims I have a second account, which is not the case. Additionally, I received an email from Amazon.co.uk about the deactivation of my account, even though I intended to sell exclusively on the German market. Despite repeated attempts to contact customer support, my request has been denied so far. Is there anyone here who can assist me with this urgent issue? Also, when I click on my name, four stores appear. I've heard this is a common error and would like to reverse it. How can I do that? Can someone please help me?