Accredited Interchange LLC review: They increased rate for 25% and didn't refund

I contacted the representative of Accredited Interchange LLC. I asked about the changes in the rates and the representative after the conversation has made changes. When I received the statement for the first month, I noticed that the rate was higher for 25% in comparison with my previous processor. I made a complaint and the representative said that I would get refund. 6 weeks have passed and nothing has happened.