I had a subscription to this magazine that expired last year. I have cancelled this subscription several times. I continue to get letters threatening "my good standing" with the publisher. I have been assured via email that my account is cancelled and I continue to get the harassing "IMMEDIATE PAYMENT REQUIRED" invoices. Every time I get one, I contact the company again only to be advised that my account has been cancelled and to "disregard any further invoices". It seems that they do not have any communications within their company because I have now received an "immediate payment required" invoice that threatens to turn me over to North Shore Collection Agency. How do I prevent this when no one communicates?