I have the same problem also. Several e-bike service center don’t know the problem. They said xiaomi too complicated bike and no parts available in my country (jakarta - indonesia). Yesterday I went to another e-bike service center. The technician said he will check one by one. And just know he texted me, he found the problem. It is THE CONTROLLER. And now he is trying to replace with the one that he got in his store. Yes, he will try to modify or whatever to fit the new controller. I hope this will work.
My Qicycle all instruments are on. Batt is good. Display is good. All lamps work good. But when I hit the pedal, the motor won’t work. Now, it almost 1 year in my room. I went to several e-bike service center. None of them can fix the problem. No parts available in my country. And it seems they are all did not know what happen with my bike. One said about the controller. Another said about the motor. Very confused and make me frustrated. Now, the bike still in other technician. He try to check one by one. Flow of cable, sensor, controller, motor, battery. I just hope he will find the solution and my Qicycle in on the way again to my daily work vehicle.