You knew they were also locked when they asked to lock you up, but you had no idea they expected you to match the time they already had in their belt, and since she was Ace it wasn't difficult at all for her to last the 3 years she already had.
Tied down, caged, and teased for hours. This was the reality of your weekends from now on, however your mistress made it clear the cage won't be coming off on the weekdays.
First you wore panties, then you dressed up, now you are locked in a cage that you lost the keys for and there is only one way left to feel release. Let's hope you are a fast learner.
You never expected your house maid would find your key and then blackmail you to stay her little toy when she caught you wearing your cage and took some photos. If you fired her, she would just release the embarrassing photos.