harrasment from call centre agents

i have been harassed on numerous occasions by African bank call center agents collections department , i have just recently went under debt review , and i have explained on numerous occasions, and my debt review agent has supp**** them with full documents that confirms , this , buy i am still getting threatening calls and sms from the bank. i am worried that they will be debiting my account as well, because clearly , they don't listen and don't give up on calling and harassing me even at night .