Hawala is a totally illegal system of money transfer, a traditional system of transferring money used in Arab countries and South Asia, whereby the money is paid to an agent who then instructs an associate in the relevant country or area to pay the final recipient. As you export your shipping bill would be prepared by CHA, that shipping bill would be linked up with bank, money received via Hawala would not be via bank , so it would show your Shipping Bill Outstanding in bank, if money is not received in 6 months can be extended to 9 months in many cases, then RBI is going to impose penalty on firm or might blacklisted the exporter. So always receive money via banking channel for exports, once money received via bank your shipping bill would be marked as closed and you would be given eBRC, i.e electronic bank relization certificate. its the document required to get an Export Incentives from Government