Poor service

I ordered 2 sneakers last year in October 2022 and only one pair was delivered. When I enquire about the outstanding pair I'm asked to provide my order number #5408 and then nothing happens only to get blue ticks. Right now I am frustrated because I was happy with first pair, but now I fear that I got ****med. It's been 4 months now. And u can only communicate with them via watsap How do I take legal action? Anyone