Hi @EdithVR, sorry to hear about this. 
I have translated your question to English as this is an International forum, please post any replies in English and it will be easier for me and other users to assist you.
Are you doing anything specific in the device when it's turning off? Can you start the device after it has been turned off, or do you have to wait a while or connect the device to a charger?
To start with, try restarting your device in safe mode, so we can see if any of your downloaded applications is the cause of this behaviour.
Let me know how it goes!
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