FYI
Just bought Nokia 3.1 Plus. The device is mine I haven't been a customer for 6 months. They won't provide the unlock code.
Purchased the unlock code via 3rd party.
Problem: When you place a non cricket sim into it (AT&T, T-Mobile etc.) the device will not even recognize there is a sim inserted; the unlock code pop up box doesn't appear.
Problem 2: *Enter your unlock code: #pw+unlock code+1#
To enter the letter p, press the * (asterisk) key 3 times.
To enter the letter w, press the * (asterisk) key 4 times.
To enter the + sign, press the * (asterisk) key 2 times.

* Either Nokia or Cricket disabled the p,w and + input commands on this device;pressing * or # per instructions above does not produce p, w or +