Are you absolutely certain that this is how it happened (this is important. because if it can be proved so, then the workmen are liable for the cost of bringing in your organ builder.) This is, in any case, what you should do. Presumably, there is an individual organ builder (or firm) who has a maintenance contract with the church?
The reason I asked the first question was that, even with only one rank on the chest (the Tromba), it will be heavy (and also screwed to the supporting building frame). with the combined weight of the chest and the pipes (very heavy) it would be difficult to kick the chest in such a way as to unseat part of the under-action. This should have removable dust covers (of wood). In addition, the magnet will be fixed with screws as part of the under-action. If the design is anything like the other electro-pneumatic actions which I have seen and worked with, I am not sure how this could have happened in this way.
However, contact your organ builder* and tell him what the problem is. I would recommend strongly that you get in a qualified organ builder for his assessment. There could be other problems.
*If there is no-one who is contracted to the church, please let me know (by PM, if you prefer), and I can recommend someone who should prove reliable.