A wobbly fan is common and usually easy to fix.
First, turn off power and tighten all screws, including those that attach the blades to the brackets and the brackets to the motor.
Check that the blades are level by measuring the distance from each blade tip to the ceiling. Gently adjust bent brackets as needed.
Use a blade-balancing kit if wobbling continues. If the mounting box is loose or not rated for a fan, consult a qualified electrician.