I bought a ZinoPro in August of last year (s/n BAH070F140****). I recently crashed the drone flying backwards. Now the following problems have occured: 1- I keep getting a calibration error. 2- The aircraft will not respond to some commands. 3- Gimbal not working properly. 3- When I get it to land, it descends rapidly until it hits the ground. 4- The propellers will not shut down unless I remove the battery. I love this drone, please let me know where I can send it to be fully checked and repaired. Thank you.