Xiaomi Mi2S - where to find GOOD quality display+touch+frame parts?

I am using a Xiaomi Mi2S and I am facing increasing difficulty in finding good quality display+touch+frame assemblies for fixing my phone.
The last two I ordered (from Europe or China) are clearly not original and faulty. They degrade after a short time (either the touch layer or the display).
Some hints from users?
Thank you and best regards,