Scam phone number pop up won't go away

While in lock mode, the pop up +1(844)330-1440 appears. Cannot actual active either the Cancel or Call button. Can't x out of it. Tried to restart by holding power button down, but cannot swipe to shut to down because the pop up is 'active'. Tried holding the volume up and power but called SOS/911. Saw the tip to press and release the volume up, then volume down, then hold the power until the apple appears. No apple appears. Any recommendations?