Lenovo India - Lenovo ThinkPad bad delivery Lenovo does not care to fix the issue

Order No: **********
I ordered a ThinkPad from Lenovo India online store after checking configuration offered. I even called their call center and confirmed the configuration offered before ordering. They delivered the product without Windows ** OS to my shock. When I called them, they say OS is not part of the deal. I sent them the order confirmation I received which clearly shows OS is part of the deal, Despite providing proof, they were not willing to honor the deal. Then they were asking me to prove that OS is not installed in the laptop. I had to send them pictures and videos just to prove that I am not a liar.
I have been following up with Lenovo since ** days. They give a standard response that they are working on it. Their internal departments are blaming each other for the mess. Now they stopped responding. I have exhausted all options, no success: Lenovo Call center, Lenovo customer care email , Lenovo India Twitter, Lenovo India Facebook. All give a standard reply that they are working on it. Not sure what they are working on. They are definitely sleeping on it.