Worst courier service by DTDC and the losses caused by it.

My shipment having dtdc C/n D91604039 was sent from Delhi on 11th July 2020 and it reached DTDC Patna hub on 15th July 2020 at around 3:50 am in the morning. But I have not received my shipment yet. I already lodged a complaint regarding this to DTDC on 17th July 2020 at 10:51 am, case no 16895248. I was promised that I will receive my package within 24 hrs. But since then, everyday DTDC customer support team are making fake promises and doing nothing. After wasting my 8 precious days, I was asked to collect the package from DTDC hub Patna. When I went there on 24th July 2020, after wasting my 3 hrs, I was told that the sorting of the shipments was not done till date so they could not find the package and finally asked me to come after 2 days. I would like to inform you that this shipment contains N95 masks whose market value was Rs 30000/- at that time and now its less than its cost. Also because of this I lost my credibility and further orders. Kindly suggest me what to do next ?