Am I liable to pay back CDA classes if I decide to leave the company?

I work for a daycare and they offered to pay for my CDA classes (child development associates). I started the classes in October with a few other employees. I decided after recent events to find a new job and I put my two weeks in today. Now way before I even began CDA classes a few of the employees at my job said before they made you sign a contract stating that if our company pays for your CDA classes then you would have to stay with the company for two years if you decided to leave then you would have to pay back the money that was spent on the CDA classes. None of us signed that contract. When I talked to boss about what we will do about CDA classes she told me she will have to talk to someone higher up. She said worse thing that would happen is we would prorate based on how many classes you had attended. But I told her I’m not liable for paying any money back since I never signed a contract. Am I right or wrong? I don’t wanna be stuck with paying money back when they never had me sign a contract.