I understand your frustration. My wife and I have a similar issue with our LG LM-K500MMs. They don’t play well with the Bluetooth in the car. It also doesn’t work at all with the Bluetooth in my hearing aids.* We can’t return them because MetroPCS is one of many companies who took advantage of the opportunity to “protect”** their customers by putting the kibosh on returns.

LG are also Chinese like your Xiaomi so taking this together with your experience, maybe Chinese phones are something to be avoided.

*I obtained a list of compatable phones from my audiologist…after I was a already stuck with this one! So frustrating!

** thanks loads MetroPCS. Your former free and easy return policy was sure messing with me!