1. Well,if the PDCs were issued in discharge of legal debt which was so in this case then subsequent instructions not to deposit the same of recovery of the loan amount is not enough unless in lieu thereof hard cash or other acceptable mode of payment was offered.
2.So the creditor in this case committed no illegality to place those cheques to recover its loan amount.
3.in this situation your client better negotiate with his creditor to settle amicably. Otherwise he would be soon entangled in web of litigations making his life too difficult to live.