Whether you have such dues or not ?
whether you have received such notices and Credit card was cancelled by the Bank or not ?
These are the primary issues, whereas you state you are prompt. First get the statemen of accounts and notices issued.
If their accounts are misleading, fight it out through Consumer Forum.
The tactics being adopted by outside agencies may disturb your peace of mind and do not further get issues complicated, as they do not care for law and select the occupation only for their rude and uncompromising tactics in recovery.
There is an old saying " You should not have "Satru sesha or Runa sesha" (enemy left and dues left unpaid)
Focus on present issue of repayment of legitimate dues and do not think of what happens to your son at a later date. Once the issue is solved, you can lead a peaceful life.