BAD SERVICE CANCELLING CONTRACT

My husbands contract expired end of feb 2024. He has not used the contract for over a year as we are living abroad, but he kept on paying until feb 2024. Since then email after email, they still charging him. As if they dont read there emails. They want to contact him and as i said they dont read. Once we tell them they can not phone him, then all correspondence stop. Now I am asking HOW TO GET THIS CONTRACT CANCELLED???