SPAM & REFUSAL TO REMOVE CONTACT INFO

Old Mutual constantly contacts me thinking I am another person (Amanda). I have told them I do not know who this person is and to remove my number as they have the incorrect details. They refuse to do this and I constantly get calls and SMS's. Agents are extremely rude and hang up when I tell them they have the wrong person or to remove my number. I do not have any Old Mutual accounts and certainly won't have any in future.