My Samsung A30 switched off on its own and it's refusing to switch on. I have tried to switch it on by pressing the power button and the volume down but its still refusing to switch on.
I can understand wanting your device to turn on so it can be used. Have you plugged up the device with the charger that it came with for 30-60 minutes and do you see the phone react when you do plug up the phone?
I would also recommend holding the power button while plugged up.
Let me know if this helps!