Asessing the Working Capital Limit

Dear Sir/Madam

I have following query as banker.
one of our client have taken subcontractor works of 24.000 crore from main contractor but only simple agreement executed without any tds/tcs details.

Even Tds also not deducted,but in sub contractors balance sheet receipts are reported.There is no GST filed and filed Nil return for whole FY.
In that case how to assess the WC limit.

please guide and thanks on advance.