Hi
Please contact seller for warranty options.
Also you can try use headphones to check for music chip failure.
If everything else working correctly probably you have hardware fault (loudspeaker/connections).
Of course you can try factory reset (settings - backup and reset - factory data reset) and SPFT for full system flashing to remove some errors /bugs.
To do this you can read this updating instruction but please skip 6th step as you need overwrite all partitions http://community.umidigi.com/forum.php?mod=viewthread&tid=11
And here you have all available ROMs http://community.umidigi.com/forum-148-1.html
If you are not happy with sending phone to China and you are happy to open device you can buy loudspeaker (currently is not available) , replace and keep partially refund from sellers (if offer to you this option)
MarcinP replied at 2017-3-5 18:45
Hi
Please contact seller for warranty options.
Also you can try use headphones to check for musi ...
Hello,
I've already sent it back, and I will probably exchange it for a new one.
But yes, the headphones were working great, so it wasn't a chip problem, but a speaker hardware problem.