I am going to keep on calling them until I will get my money back!

They have stolen $4000 form my account, and now won’t reply to my e-mails or phone calls. I keep on trying to contact them in order to get a refund, but each time when they hear my voice on the phone, they hang up. They know that I will try and get the money back, that’s why they keep avoiding me. But I won’t give up!