There is nothing Apple can fix. Someone has your cell number and sent you a SMS text that your cell provider forwarded to your phone. Contact your cell provider as many have SPAM options they can use to filter these text messages. With your phone number anyone can send you a text that says anything they want and Apple is not involved at all. There is nothing wrong with your phone. Use the Report Junk button and it will also notify your cell provider that you flagged it as Junk. What your cell provider does with that information is unknown by Apple or us.
Other options include third party SPAM blockers or filtering ALL messages from an unknown sender.