identity keep calling for ex wifes new debt

Identity has been calling me and my fiancee in regards to my ex wifes debt (I have been divorced approx 3 years now) apparently my ex opened an account there last year and gave my number as a contact number without my permission, Tracing agents are now calling me and my fiancee, I have explained that i have no contact with her and dont wish to but yet you persist. Please stop.