National Testing Agency (nta) - refund not processed by nta

While performing online submission of application form for AISSEE ****, the application fee of Rs. *** was debited twice from my account. It occurred as during the first attempt the message reflected by payment gateway was that "The transaction has failed"; he was debited from my account. I had to make second attempt as the payment was still showing in pending state, post which it was successful.
I have been chasing National Testing Agency over email and phone since more than a year to process the refund of duplicate payment that was debited from my account during the first failed attempt; however, they doesn't seem to be helping in this casecase.
For reference, kindly find attached email communication.
Request your help in getting the refund processed and voicing out a message to NTA about their unprofessionalism.
Appreciate your support in advance.

Thanks & Regards
Ashu Sethi