Amerassist Settled on a claim without my authorization Columbus Ohio

I hired Amerassist to collect on a non paying customer. I paid 1200 for the first 24 accounts. I gave them my first account where they stated they made calls and sent letters for 3 months with no avai. They contacted an employee in my office and asked for an amount we would settle on. The employee gave them the amount without my knowing. I am the owner of the company and the only person listed as a user on the account as well as the only signature on the contract. Amerassist settled on the figure and collected the money within 2 weeks. They then updated their online notes we see when we login that they collected the money and we will be paid 50% of that amount. I contacted them and was given the run around for a couple weeks. Then finally I was given their corporate council's number. I was told by the company lawyer that he would look into it and get back to me. I tried reaching him a couple time with no success. I received a check in the mail a few weeks later for the 50% amount. I tried reaching him again and was told "If I wanted to dispute it I need to go through Arbitration in Ohio." Thats it. No trying to work with me at all. I hired them and would think they would at least talk to me about this. They just took the money and ran. I am going to be sharing my experience with all the Franchises in my network as well. I still cant get over them moving forward with settling this claim without my written approval. I signed the contract with them. I paid the contract amount to hire them. Unbelievable.  Jim