Huawei routers support data only, so no voice?

Nice design aesthetically. Registers on MTN's open mobile data network as a Hotspot so no voice support, customer support tried to troubleshoot it but were unsuccessful. Huawei support was pleasant but clueless and was surprised this modem had a phone port. I think that I have just lost the plot or something because I was not able to make voice work.

Data speeds are good, cell signal was solid. The settings are very limited. You can set the APN url ONLY, no other settings as far as that goes. There is another setting to select if the antennas use Auto, 2G, 3G, etc. VoLTE is supposedly supported but I couldn't test it.