For some unknown reason my Moto X has been "stuck" in HSPA+ on T-Mobile for the last day or so. It won't catch LTE as usual. So either TM has turned off LTE, which is unlikely here in Phoenix, one of its flagship LTE areas, or there is some problem with my phone. I've tried powering on/off to no avail. I have not dropped it recently. What can I do to look at and solve this problem? I'm running unrooted 4.4 on an XT1053.