Overnight Express Courier - Courier not delivered, Refund promised

I sent medicines(urgent) from Calicut to New Zealand on August *th, ****, due to Kerala floods and custom related issues they informed that my courier will not be sent and it'll be given back to you with the amount you paid on August **th, ****.
The Hrb Manager of Kochi, was held responsible for this, I kept on following him for the refund and Everytime he would say *days or *days.
Later around October, he told it should be processed from Delhi and the process takes time and for anything above Rs. *,***, no cash and only a cheque will be provided on the sender's name. I agreed to this and still waited and again the same statement of *days continued.
I thought to complaint further and took this to the customer care executive of Kochi and she did not respond well, she just says I don't know anything sir, please contact the Hrb Manager, and that Hrb Manager gets hundreds of calls daily and Everytime I call him either he doesn't pick up and cut my calls and avoid it.
Where can I complaint more further for my lump sum return! ? My medicines are wasted and my courier charges and time consuming calls to the Hrb Manager and team.