Is ITC reversed if Nil Refund is filed for a particular period?

Hi,

My client wants to claim a refund on ITC for the month of October 2019. Before that the client has never asked for a refund as she was using part of the ITC to pay her mothly taxes.

If we file nil refunds till September 2019 will the accumulated ITC till September 2019 be reversed to the government or does she still get to keep it to offset her future liabilities?

Please advice.

Thanks

Karan