Stuck during ERASE.

I needed to get a replacement iPhone 8 as it would not connect with internet after recent 14.5.1 install. Verizon agreed to replace phone. I turned off Find My Phone, the selected ERASE iPhone prior to sending back to Verizon. The phone got stuck at maybe 5% through erase for over 60 minutes with no change. I cannot shut it down or anything. Suggestions?