I have MetroPCS and a ZTE ZMAX Z970 phone with Android 4.4.4
This app appeared, I don't know exactly when, and it's got some worrisome permissions and I want it off my phone, but it has no uninstall option and there's nothing on Google Web Search about it.
It looks goofy enough to be malware.
(Click image to enlarge)
pm list packages -f -s | grep "Assistant"
.com.zte.heartyservice