I have a small website which sells trinkets. The site is a zencart and although by default when a person signs up they are offered the option of joining a mailing list, I have turned this off and don’t operate a mailing list.
The only time people get automatic emails from me is when people sign up, and then when they place an order. So people should expect an email saying thanks for signing up and one for placing an order.
Over the last few months I’ve got a couple of emails from people (who I can’t find as customers of my site) who ask to be removed from my mailing list because they haven’t signed up to it.
Has my site been hacked or something. I’ve asked my hosts who just tell me that I should install one of their modules which tracks emails or something. Not very helpful.
I’ve asked the people who are complaining to forward me the offending emails but so far noone has bothered to.
That is a spammer trick. They have found your email address somewhere, and they use it for the "from" and "reply-to" addresses in their spam emails. It looks like it is from you, but it is from a spammer trying to sell Viagra or something. There is really nothing you can do from your end. If the spam victim checks the header of the offending email, they will see it is not from your ip address, but some ip located in Korea or Singapore.
ADD: The reason is that after the spammer sends a few million spam emails, that "from" email address (yours) will be blocked by about half the world’s email servers. Then the spammer will go back to his/her spam database and pick the next email address in the list. When it is also blocked by half the world’s email servers, back to the list.
The spammer could have gotten your email address from zencart, but if you have your email address on your website, like a "Contact Us" page, that is where the spammers get 99% of their spam lists. They employ a "email gleaner" bot to collect email addresses from websites.
And if the spammer can find an "open relay" email server that is set to queue mode rather than interactive, that will present a different challenge for you. Not only will half the world’s email servers think you are a spammer, but if the spam email cannot ultimately be delivered by that "open relay" server, the reject email is sent to you! Maybe hundreds of them.