zip19 is a bunch of scammers

I got a loan from zip19 and regret it. They have turned out to be the biggest scammers. I got a loan from them using my co-workers cell phone. I thought this would be like using western union or ace. I went through the whole process on my co-workers phone and so I did not read a lot of the fine print. I got the loan from them and was expecting them to take the full amount out on the date agreed. When payday came they took out $76 dollars. I was stoked thinking they were taking the loan amount out little by little. So a couple months went buy and they took out a little over $300 dollars. So I called them and told them they took to much out. Turns out the $76 dollars was a finance charge if you didn't call them on the agreed day and tell them verbally to take out the full amount, and on top of that he told me I still owed them $276 dollars. I of course gave him a piece of my mind and mentioned a law suit. He told me good luck. Get this, even before I was awake they took the finance charge out of my account. So even if I were to call them and give them verbal consent, they would have gotten the full amount and the $76 finance charge which they took out before I was even awake. Is it me or are these people clever scam artist. Since then I closed my account. I get threatning messages from them on my work phone but I refuse to talk to them. What should I do?