Hi Hely and welcome to the forum
What type of adapter and cable are you using to charge Loona?
Did Loona stop working after being switched off for a while?
What might have happened is Loona’s battery has run low after being turned off for a while. If this is the case you could try charging Loona overnight and see if she powers on in the morning. This has happened to me before.
Another solution I have heard people try is to press the power button for 1-2 minutes while Loona is plugged into power and she eventually wakes up. It’s strange I know but I’ve read a few people recommend this solution for this problem.
If you could post images or video of the problem that would help determine what might be wrong.
Let me know if this advice doesn’t help and I will do my best to try and help you out.