phone shuts off and won't turn on

Please follow the steps in the following link for support with this issue: If your iOS device restarts or displays the Apple logo or a spinning gear unexpectedly

Mine has been doing this for months. I have the iPhone SE. 2 yrs old and in good shape. I tried updating the operating system, restarting it. It has been going on for months and just seems to randomly shut off. To get it to turn back on I have to hit the volume up, volume down and then power button. Sometimes do this 10 x sometimes 30x to get to turn back on. It has really become a problem especially with the phone used to call uber, pay for things, communication with daycare,etc. I tried calling verizon and they want to upsell me to buy a new phone. I need Apple to figure out how to fix this.