Gst tds input credit in the case of gst deductee registration is late

My client is a local authority (Gram Panchayat) has made payment to a trust who was not registered while making the payment with GST.
So payment was made in the month of Dec,2018 and GST registration has taken in the month of Jan,19 by trust and was active from 16th Jan 2019.

So can we file the GSTR 7 for the month of Dec.18 by mention the trust GST no?? In which month we should account GST TDS of 2% which has been and make the payment ? Can the same be considered in the month of Dec