Flipkart OmniTechRetail - Discrepancy in serial number of Sony Bravia on TV and Tax Invoice Warranty given by Flipkart Incide

I had lodged a complaint with Flipkart regarding Discrepancy in serial number of Sony Bravia W***G (priced at Rs. **,***) on TV and Tax Invoice / Warranty given by Flipkart, on October **, ****, which is being handled by Flipkart ecsalation team. As per our conversation on call, they were to come up with a revert within * hours and a resolution within ** hours, as specified in their email. It has been ** hours since then. There has been no resolution neither update from them, except a stray phone call, where they volunteered to return the product, with weak claims about refund being issued within ** hours of the return. For which they refuse to take any responsibility, saying the refund would be entirely the seller's responsibility, for which they can't offer any assurance!! Neither would they email us guaranteeing the same!
We suggested the idea of receiving a cheque for the said refund, which they adamantly refused as 'this was not their company's policy'. They want us to blindly trust them after delivering a dubious product and also after the fact that it took * whole days for them to make this phone call! When we confronted them with the question about what if the seller doesn't send a refund after the return, they were tongue tied and had no answer.
All that we need from them is an assurance email taking full responsibility of the refund, in the case of failure on the part of the seller to do so. Or at best a cheque issued in my name for the refunded amount during the return process. But they seem to hide behind their 'policies', when it comes to that, with a clear refusal to take any real responsibility. After which the agent rudely disconnects the call. So far there has been no real resolution. Need a quick redressal of the grievance caused to me, and a refund issued with immediate effect.
Vinay