National Highways Authority Of India [NHAI] — Panipat toll plaza issue

Address:

Panipat toll plaza

On 4th july 2020, i passed through panipat toll tax with my family. My fastag was having ample of money so that i can easily pass. But on the card reader, it was showing "blacklist tag" and barrier didn't open. I asked executive about why it happened, but he was rude and was asking to pay 6 times the amount that i need to pay through fastag.
But within 2 minutes, the reader read my fastag and barrier got opened. I again asked executive why it happened he wasn't aware if the fact.

My car registration no is: hr06-z-1791.
Please revert with why it happened and what can be done to stop such problem in future.