Employment Garden

I have been looking for a job and signed up to several web sites that offer help with finding jobs. I received an email from Employment Garden listing several jobs. I never signed up for this web site and when I tried to unsubscribe, the unsubscribe page cuts off contact. That makes it impossible to not continue getting their emails. Seems like a shady company that won't allow people to unsubscribe. And, how did they get my email address anyway?