DualSim Phone is only 1 slot Sim

I am very disappointed in MTN. I got a contract for a Huawei P Smart 2019, which the phone is advertised as a dual sim phone. Today I have added a second sim and see its not working. I really thought maybe I am doing wrong. I done my research, looking into the manual and trying to do trouble shooting myself. Unfortunately no luck. I went directly into a MTN shop stating it is not working as a dual sim phone. All I was told it's a 1 sim slot only. False Marketing MTN. I want a dual sim phone as advertised. Dissatisfied with the service and the product.