If you have a Kyocera DuraXV Extreme or LTE phone and you're not receiving chat messages, you need to call Verizon tech support and ask them to enable feature code 83856 (CDMA-less provisioning). This setting is somewhat unknown by most Verizon tech support people, so specifically request that you "enable feature code 83856 for your phone." Within a few minutes the tech will locate the specific feature and enable it for your phone. (In contrast, if you ask for CMDA-less provisioning, they might not locate the right feature code.)
Note that you must call Verizon tech support with this request -- the in-store clerks in Verizon stores can't help you with this feature code activation.