First, copy writing is writing copy–copyright is the legal protection of works.
As to your article, you created it and thus own the copyright. While you gave others permission to utilize, within your terms, that permission can be revoked by you at any time–unless you gave the party a perpetual license under those terms, which you most likely did not.
By not including your link or disabling it, which happens a lot to me, they are violating your copyright.
To start with, you can send a simple email/letter to the offending party and CC a copy to their hosting company. By sending a copy to the host, you have now notified them of an illegal action on their network.
If you don’t get any response, send certified copies of the letter in the mail with RRR (return receipt requested)–this gives you proof of delivery.
The host will most likely take some course of action as not doing so becomes negligence since they were notified.
Should you still receive no action, small-claims court is the next course of action. If the article was registered with the U.S. copyright office, you can sue them for “copyright infringement”.
Seek out an IP lawyer if the matter escalates and do your homework before doing anything. This post is not legal advice.