Tablet not accepting unlock pin

[DotSully]

Hi! 
My mother in law, who is not tech savvy, purchased a Samsung Galaxy Tab A7 Lite 8.7" 32GB 3GB RAM. I set it up for her and all was fine. Now, it asks for pin and won’t accept the one we set. All it does is say “too many incorrect unlock attempts, try again in XX minutes” it will not allow us to power down, reset, put it in safe mode, anything else. Just an option to enter a pin and then more time added when it doesn’t accept what we set. We did not set up a samsung account and there is no option to factory reset from her google account. Only the ability to remove it from her google account. We just want to factory reset and start over. Im very tech savvy but this has me stumped! Help!