I actually opened it! I phoned the locksmith beforehand and it would of cost me $40 to $60 for unlocking it. After figuring out how deadbolts work, I tried unlocking it using a flatheaded screwdriver and needle-nose pliers, and I got it unlocked and opened! If anyone ever has this problem, use a flathead screwdriver to turn the little square inside the doorknob until it clicks, then use the needle-nose pliers on the bigger square to turn the knob. Nonetheless, thanks for the help!