health sciences inst Took fees out of my bank account without authorization or without my knowlege,and I have no idea how they obtained my information nationwide

I was checking my bank account and noticed an unusual withdrawal and when I called the phone number they said I subscribed with then in September.Which I had not and after looking at the time stamped on the withdraw which was at 1:17 a.m. When I talked to them they agreed to put the money back on my debit card,and I have no idea how they obtained my information but they had my user name as well as my password.And I am not even on the computer that time of morning.I am contacting my bank and warn them of unauthorized withdrawals and hopefully put a stop to situations such as this.Just be wary of unjustified withdrawals from your accounts