I would not worry about the one you got. They can not bill you because you never ordered it. Just make sure you return the ones you receive in the future. Try to find a phone number or web site to make sure they got them and stop sending them.
I once ordered some books for my son and they kept coming every month. When the price got too high I started returning them but send me a bill for them. When I called they claimed they never received them. I not is not true. After a long argument that lasted several weeks I was credited and didn't have to pay for them but it was very aggravating.