Call barred

I was contacted yesterday on 03/03/2020 from an unknown number, the person calling claimed to be from cell c. He wanted my personal details to confirm my identity with Cell c. I refused to give him and droppes the phone. Soon after the call i discovered my phone has been barred from making calls or sending sms. I do not have anotjer cell c sim so I can not phone cell c to inquire about the reason to bar outgoing calls on my sim. My account has been paid in full and as a matter of fact I am paid in advance. This is very very irritating.