Terrible Customer Service Evetech

I have returned my device because it is not working. It has been 2 weeks now trying to get an RMA and to date, they are struggling to advise a way forward. I am dealing with a guy called Darien. I have been trying to reach them on the phone and they keep promising to call me back and that hasn't happened for the past 3 days. They are not responding to my emails as well. Terrible customer service.