How old are these children?
You say they have literallyhad it playing all day and night for 6 months?
Changing that is going to take some major adjustment, but it’s doable.
To be honest, if they’re young enough not to clock what you’ve done, I would be tempted for the ipad / whatever they’re listening to it on to ‘break’ / be ‘lost’ next weekend.
They will be upset, but hopefully they won’t direct anger at you. This experience will just let you (and them) see that they can in fact cope without it. Yes they will melt down, but it will be interesting to see how long this lasts & how they get over it.
The ipad can be ‘fixed’ / ‘found’ on Monday, but they and you will have a glimpse of what life without Matilda looks like (and tha it is survivable).
This happened for real last year in my area when there were storms and power cuts for days. Once the batteries on their gadgets ran out, all the kids addicted to their gadgets had to find something else to do. It was amazing what they were in fact capable of doing when they had no choice.