Dell - Product not delivered

I ordered a laptop "Dell vostro ** **** with Ubuntu Operating System" on *rd july, ****. I paid the amount of Rs **,*** via BHIM UPI. Same day I got a mail saying "we have received the payment. You will receive an order confirmation mail very soon". I waited for * days for the order confirmation email and then I tried contacting Dell for the order confirmation but they never picked my call, so I post this entire issue on Twitter. There I received a message from @DellCares asking me about the entire issue. I provided them with required information and Internet Receipt no. mail screenshot. Next day I got a message from them on Twitter saying they don't have that model, due to some technical glitch it was showing on the website (their technical glitch cost me of ₹**K) and they will cancel my order and will refund the entire amount. but I never heard any response from their side. Meanwhile I sent them tons of mail and called them many times but I did not receive any answer from their side. Today is ** july **** (** days since they told me about the glitch) and still i get no response from their side. I asked them about the refund but they never replied. Their phone rings for hour but they never pick and sometimes they hang up even.