Condo Rent Misunderstanding with co-tenants

I have a situation. I used to rent a condo unit with 4 other people. We had a contract with the owner to rent it until may 31. we were required to pay security deposit which shall be returned at the end of contract. But I had to move out last january so I searched for my replacement and informed the owner. I asked from her the same amount of security deposit that I paid, so that when the contract ends, she will get the deposit I paid to the owner. As a result, she cleared me of my responsibilities and I moved out. Then, the remaining tenants decided to move out on march 31. The owner agreed provided they will not get the security deposit which is equivalent to 3 months rentm as payment for the last month's stay and for repairs. But my replacement is asking me to give back the money she gave me. I don't think that is fair. What should I do?