Samsung Galaxy Tab S froze on a website and won't power down

Galaxy Tab S: Froze up while on a website. I did one hour of online chat on three separate occasions. Bottom line - hold power button, volume button and home button down simultaneously, pray and count to at least 20. I did it with the device on the charger and then not on the charger. Finally one of those times it worked. Do yourself a favor and write down the serial number and other information if you do an online chat. The numbers are smaller than the head of a pin.