What are the legal action should take by the purchaser if supplier not filled gstr-1 for sale made

If payment not made deduct GST amount and make payment and deposit GST on RCM, if payment made then, at present, there is nothing you can do, just take ITC in GSTR-3B if you have Invoice and wait until govt opens GSTR-2 then enter such invoice details there & submit and wait for the seller action on the same.

Further, if seller don't pay even after that also then it might possible that you have to reverse such ITC along with Interest.