The Supreme Court on Monday refused to halt an inquiry ordered by the Competition Commission of India against e-commerce firms Flipkart and Amazon into allegations that they promoted selected sellers on their platforms, Live Law reported.

Amazon and Flipkart had approached the Supreme Court challenging a Karnataka High Court order, which had in June refused to interfere in an order by the Competition Commission of India directing the inquiry.

The Competition Commission’s order in January was based on a complaint filed by traders’ body Delhi Vyapar Mahasangh, which had alleged that Amazon and Flipkart were giving preferential treatment to some vendors. They submitted that the e-commerce firms had indirect control on the operations of these vendors, especially in the case of launch of smartphones, according to Live Law.

The two companies then moved the Karnataka High Court challenging the order. However, the High Court on June 11 dismissed their petitions. Justice PS Dinesh Kumar said: “It would be unwise to prejudge the issues raised by the petitioners in these writ petitions at this stage and scuttle the investigation.”

The single-judge bench order was upheld by a division bench on July 23. Amazon and Flipkart then moved the Supreme Court in the last week of July challenging the verdict.

On Monday, the Supreme Court bench of Chief Justice of India NV Ramana and Justices Vineet Saran and Surya Kant refused to interfere with the High Court’s order.

But they agreed to give the two e-commerce companies four more weeks to submit their reply to the Competition Commission. The original deadline was set to expire on Monday.