I owe cellphone insurance I never took

On 06 March 2020, I paid up my Edgar's account. Yesterday (12 Oct 2020) I received an sms that I owe Edgar's R473. I called their contact center and was sent from pillar to post. Finally, Chane said the amount I owe is for the cellphone insurance. I have never took a cell phone insurance. She advised me to call ***, but the number rang unanswered. Can I please have proof of when I take the cell phone insurance. Clear my account and close off this account.