TDS ON CREDIT NOTE

We have paid to vendor amc charges quarterly ----- rate is fixed

I.e 42000/- quarterly advance

We have paid amc from OCT 2019 to DEC 2019 - 42000/- plus gst (tds is deducted 2% 194c and also tds return filed )

Now we have to deduct 14,000/- for not doing amc for nov 2019 month)

So he has given credit note - AMOUNT 14000/- plus gst

We will deduct this amount from JAN 2020 TO MAR 2020 bill payment 

bill amount - 42000/-- plus gst LESS 14000/- plus gst (credit note)

AMC Expenses in books - entry will DR (42000-14000) = 28000/-)

MY question is:- 

TDS SHOULD BE DEDUCTED ON 42000/- bill amount

OR

42000/- LESS CREDIT NOTE AMOUNT 14000/- =28000/-

PLS REPLY 

THANKS