Normally if a device is having issues charging, then it has something to do with the charging port, battery, or the circuit connecting the two. Since you were having notifications from your phone itself while not charging then I would assume that it is a battery issue. Inside the battery are cells that after long use can no longer hold a charge, so you might have run out of available cells to power your device. I would recommend taking in your Stylo 4 to a repair shop near you to get it checked out and quoted on a repair. However it should not be more than $80 based on the prices in my area.