Hi @MC2019, let me see if I can help out here!
If the power key isn't responding, feels dead and isn't springy, it is most likely related to hardware. In that case I would suggest that you get in contact with your local support team in order to have have the phone examined by an authorized service technician. If you have any questions regarding the service such as routines, warranty and consumer laws, these kind of questions are best answered by your local support team as well, as they vary between markets.
I hope that answered your question!
