Voice on Nokia 225 no longer working.

Update: I drove to an event around 3 hours away yesterday, out in the country. When I arrived, I had no signal. But lo and behold! VoLTE had turned itself back on (I didn't switch anything). Excited, I waited until I got back in range, and made a call to my wife. VoLTE was still on. But the call didn't work anyway. I heard nothing. Later, she said it rang, but was just a dead line when she tried to answer.

After a couple of tries like this, I turned the phone off and on. When it came back on, VoLTE was gone.

This suggests that the 4G network signal is the thing bricking VoLTE on the 225. Once I lost the signal, perhaps the phone was able to go back to VoLTE without interference from the network.

Thanks to those who suggested switching to 2G. This works, though as people said, the signal can be spotty. In fact, I have gotten my Nokia 105 (3G and below only) to work again in the US (even though, supposedly, it does not use US frequencies - it's a European model). Since the 105 is pretty much identical to the 225, except smaller, it's a better choice.

Finally, switching to 2G fixes the problem of incoming texts having the wrong timestamp. So it seems that the weird text timestamps are a 4G issue as well.