Yes, this happened to us a couple of years ago. We had chosen our balcony cabin well in advance, then just happened to notice a couple of weeks before sailing that we had been moved. Called Celebrity and complained. They said they would move us back to our original one. But in the time they took us out of our ‘new’ cabin they discovered they couldn’t contact the people in our ‘old’ cabin so went to put us back in the ‘ new’ cabin only to find it had been booked again by some one else. Moved us into yet another cabin. So 3 up to now. We continued to express how unhappy we were and they gave us on board credit and a future cruise credit.
When we got to the pier we explained the paperwork wasn’t correct only to be told we had been moved again. This time we had been upgraded to the Royal Family Suite. ( only 2 of us).
So turned out to be a winner for us. Hope they work something out for you.