Most magazines belong to a corporation. Their subscription is handled by a different company. As an example Quilter's Newsletters is written (published) in Golden, Colorado. Their renewal office is in Palm Coast, Florida. They now belong to CK Media.You can always find those informations in an inset at the beginning of the magazine.
I would deal with the Florida office to subscribe, renew or cancel the magazine.If I am not satisfied or have problems with them, I would let the Editor in Colorado know. It is a case of the right hand doesn't know what the left hand is doing.