Can I recover money that has been auto deducted from my bank account?

I own a salon where I accept credit cards. About 5 years ago I switched processing companies. The associate who facilitated the switch assured me he would cancel the old service, and I recall signing a form as such. It has recently come to my attention that have been charged monthly this whole time, totaling over 4000 dollars (taken directly from my bank account) I contacted the company and was told I bore the responsibility for ensuring the service was cancelled. It should be noted that I clearly did not use the service in this time, no transactions were processed at all. The person I spoke with could see that there was no account activity since 2012. I also may be charged a cancellation fee in spite of not having a contract. Do I have any recourse? I cannot afford an attorney. Or, am I simply 'out' this money.