Unsatisfied with Hisense portable aircon

Purchased Hisense 12000BTU portable aircon and it does NOT cool room. I installed it according to manual in room of 3x4 meters, and set it on the coldest 16*C setting, high fan speed and cooling for 10 hours - It does not change the room temperature. I am unsatisfied with this product - it does not do what its intended to do.