Cancel my Amazon Seller Account

One upon a time, omre than 1 year ago, I was trying to operate with Amazon Seller Account, then i did a signature at Amazon Seller Central [login to view URL] But there was a problem, I never used my e-shop for nothing, since i didn´t had the necessary skills to do so. I tried to cancel ths account, but it never worked. I thought it would cancel automatically the service, since i was not selling, not loggin in, not paying for more than a year. Today I was surprised by some e-mils in my anti-spam, with payments being due every month. Every month, Amazon sends a new invoice , I tried to login to cancel the signature / service, but I couldn´t. So, this job is to login to amazon and FIND A WAY to cancel the service / subscription, in order that Amazon recognizes that I no longer want this seller account and STOPS sending new invoices. I understand that it will be very tuff to cancel old invoices, and cancelling old invoices is not part of this JOB here. But I would APRECIATE a LOT, if this could also be done. The good thing is that i still have my login and password, wich I will pass only after choosing the freelancer, since this is confidential information. All the best, Roberto