Does the cat have a collar on?
If yes, other magnetic and metal objects on the collar may be operating the door. We recommend that you seek out the owner of the cat and discuss some options for changing out the collar, keeping the cat better contained, etc.
If no, try to push the flap open from the outside. If it opens without a problem and the door is installed correctly, the latch is faulty. Please click here for contact information to reach our Customer Care Center.
If the door does not open when pushed and the door is installed properly, the cat must be using excessive force to enter. You may want to seek out the owner of the cat and discuss some options for keeping the cat better contained.