Complain with unending calls from nedbank

My mom she has be retrenched from work since last during covid so since she is no longer working we did send the documents showing that that she is unable to continue paying for her loan that she is owing at nedbank but since than they have been calling her till this day one parson after another Can you kindly help so that they stop calling her cause she has to explain one thing over and over and its been a year now since she is no longer working she has no any source of income to even pay a little that she can