The laundry room is common property. All residents should have access to the common property. The committee is responsible to maintain the common property on behalf of the owners. I would take it up with the committee that the room cannot be accessed. Are you sure the committee didn’t just change or fix the locks and your mother missed the announcement that anyone wanting to use the room should collect a replacement key?
If that is not it, then suggest to the committee that they should get the room opened and they should pay attention to the electricity outlets in the room. Is anything connected that shouldn’t be? If someone has done something dodgy with the wiring, then the committee should get it checked by an electrician if for no other reason than safety but also get it traced. If no-one is legitimately using the electricity for its intended purpose, ask the electrician to pull out the fuse or otherwise disconnect it in a way that can be easily reversed if someone does want to use the laundry room for laundry. Has the OC had unusually high bills lately?