I too received an unsolictied copy and a bill. However, I did the following:
Went to the ebonyjet.com web site and its contacts page. Right there on the page was a phone number for subscriptions. That number, by the way, is 800 999 5954. I called it and spoke to a very pleasant, polite call center agent, Deborah (could be spelled many ways, I didn't ask). She located my "subscription" and told me that it was now cancelled and that I should ignore the bill and that I owe nothing. That is of course perfectly as it should be, I don't think I ordered it, I don't want it and I am not planning to pay for it.
It seems pretty straightforward to get off the list - but I agree with the poster - we should never be in this position. Kind of reminiscent of the book club scams of yesteryear. I do plan to send my copy back to the publishers because I don't want it, and don't want the accusation that I "stole" it to be leveled against me.
Interestingly, I think Yahoo must have been the source for the magazine - because I used my middle name when signing up for Yahoo mail (and that is the only site that I used my middle name/last name combination + home address). So I will be asking Yahoo if they have some kind of relationship. I have done this kind of tracing for years - different combinations of first/last names for things I sign up for, and then see which connections are made. Yes, I probably do have too much time on my hands!
Anyhow, good luck on getting your subscription canceled too.