Recovery on Exports Goods to importer in Mumbai

I have exported goods to a buyer in Borivali Mumbai India in May as trial and then in August as final order. The buyer agreed for 7 days payment terms . Once goods were delivered they went back saying they had issues with getting payment from their client and asked for more time. We agreed with a 3% per month interest surcharge. The importer paid 1/3 of the payment in December and still claimed to have problems. Now they have stopped accepting calls and responding to WA messages etc. I would like to know what my options are including if I can let the required agencies in India know and stop this person from perpetrating any further frauds.