E-commerce site Selling in-authentic product on basis of misinformation

Recently i bought a product from an e-commerce company name rhymes with jipchart, it was an extended warranty (the site claimed that it was an official brand warranty),now the product warranty was not extended i reached out to both the parties:

1. The brand is claiming that the e-commerce site is selling in their name is not from the brand and is a third party even though that e-commerce site is using their name.

2. The e-commerce site is asking for job sheet and in written, while the brand is telling when the warranty is not from them they are not liable to provide jobsheet and the mail is to be treated as official company response.

3. Despite the official response from brand,the e-commerce site is parroting the same and just delaying.

4. Raised a grievance on NCH, the company replied and closed it and didn't even address the issue and made it about the laptop while the issue was with warranty extension.

What are my options now? Can this case be treated as misinformation/fake promises by the e-commerce site of selling fake product as the brand denies it being authentic?