Credit card division insistant calls

This review concerns the credit card division. My son had a credit card with them, and he is under debt review. We continuously get calls on our home phone from this number *** and when you answer it, either you get nothing or a recorded message saying this call is recorded and then nothing. If you do actually get to speak to someone, they ask to speak to my son, and I tell them to contact him on his cell phone and to update their system to change his contact number. Why they need to contact him instead of the debt review people I do not know. I have asked why we keep getting these calls and they say sorry the calls are system generated. I cannot believe this department is so inefficient.