Northern Leasing/SKS Associates Unauthorized Debit New York, New York

I finished paying off Northern Leasing for my equipment lease (or so I thought) this January, I called for a payoff amount on my loan and sent the check which was cashed by them. So when I saw that they debited my checking account again in February I called them. They told me that they would credit my account back, however, on March 30th another debit was made by SKS Associates for $100. I didnt know who SKS Associates were until I found this website. I have to admit Im a little scared now. Maybe I should close my business account before they take more of my money.