Tcl Holdings — Warranty claim

I’m filing this complaint due to the horrendous service provided by TCL customer support team. My sister purchased a 43’ TCL smart tv unfortunately the display is not working. The product is within warranty but unable to claim it due to loss of invoice copy. My brother in law who bought the tv passed away not sure where the invoice is misplaced. Tried contacting the dealer who sold the tv but they have shut down their business - Chellamani and co. I was able to get the loan copy as this product was bought through consumer durable loan. I spoke to tcl team and was asked to email the document to their email address. As requested I shared all the details almost 5 times but they keep saying no emails received inspite of verifying the email address. This is absolutely unacceptable behaviour from such a reputed company. I would like to get an end resolution to get the warranty claimed