Ajio — Item not delivered

I have order 3 items from AJIO on 31st of Dec. Out of which 2 items were delivered but one is not delivered to me and AJIO claims it is delivered to me. Have raised multiple complaints with AJIO but not use. They have simply closed my complaints without any resolution. Also I have shared my apartment cctv footage which clearly shows no orders were delivered during that time. Don't know how to escalate this