By the controller, I presume you mean the radio transmitter.

If the plane is fairly new, take the whole package back to the hobby store. They may swap it for a new one. Be sure to bring your receipt. Or they may send it in to be fixed.

If it is not new, and medium CA will not hold, clean off all other glues and try some 5 minute epoxy. Make sure it is at room temperature, above 65 degrees or it may not set well. Let it sit for an hour, to be sure.

Be sure the glue is between the pieces when you join them, then spread it up and down all sides a little to form a wrapper.