Long wait for exchanged product

I bought makeup online including foundation that was the wrong shade. I then proceeded to arrange for an exchange. Mac had their courier pick up the foundation and was promised that once they receive it the correct shade would be dispatched and I would receive an email with the tracking number. It’s now over a month that I’m still waiting for my foundation. I call and text on their watsapp number but nobody seems to know the status of my exchange. They promise to reply on email with the details which they don’t do. And they promise they will have my Order out and I’m still waiting.

I am greatly disappointed by their service and don’t think I’ll ever purchase from them