Smart ATO back rusted out!

Hello, hoping for some help and direction as to why the back of my smart ATO has rusted expanded and almost completely popped out of its housing. Due to this the rust has begun to discolor the diamond shaped piece of plastic that is in the circle that the magnet encompasses. Therefore the ATO is no longer functioning properly and the alarm goes off constantly. Aside from worrying about the ATO not working as it had perfectly till recently,I am now worried about the rust crashing my 350 gallon reef, this ATO is in a 40 gallon sump. I've seen online that this is happened on occasions, and just wondered if it was a defect and a one off, Or a more common occurrence of your folks are aware of. It would be wonderful if you would be able to send me a new back piece to the ATO so that I can get everything back up and running. In all my years this is the first time I've had any issue with any product you folks manufacture.