You may have to wait to receive a “bill” (which is not a legitimate bill, since you did not order a product) from that company. This may be a different business from the magazine, which really adds to the confusion. There should be a phone number or website listed on the bogus bill. Use that to contact the company and inform it that you did not order the subscription, and tell them to cancel the subscription ASAP.
Check your credit-card bills carefully, as some of these sneaky scammers will automatically charge your credit card if you don’t cancel the subscription.
When anyone goes shopping for me, I make my list and, when needed, I give the person a label, along with any coupons. It makes the shopping trip easier. The labels go back in a bag when the shopping is done.