Problem on access to AK8975 (IMU 9DOF - MPU9250)

I bought via eBay one 9DOF - MPU9250 and after connecting to an Arduino Uno , I can not connect to the magnetometer ( AK8975 )
By I2CScan I see MPU9250 responds only on address 0x69
When I read the register 0x75 ( WHO_AM_I ) on 0x69, it returns 0x71. Correct.
However, when I try to read the register 0x00 on AK8975 address (0x0C , 0x0D , 0x0E or 0x0F) I always get FF
What should I do?
Thanks in advance.

I just do the same test with another MPU9250 chip from another manufacturer and the other responds 0x48 . I think yours may be defective.

Ok so can you send us back the IMU please. My team will test it.