Open Question: If a company policy is refund before 30 days, what legal rights do we have returning something after 30 days?

I ordered a product on line that offers a "30-day moneyback guarantee". In addition, the company is sending me on-going vitamins every month and charging my credit card. I want to stop receiving the vitamins even though it has been over 30 days. Do I have any legal rights to get them to stop even though it has been after 30 days? I would also love to return the original product, but understand I missed the 30-day deadline (it has been about 90 days). But I am mainly concerned about the on-going vitamin shipments/charges. Thank you.