the drone failed to ascend to the set altitude before it starts to move towards a building and crashed my mavic pro. why is that so? is the software save to use?
We are very sorry to hear about the crash. Did you try to takeover manual control of the drone using the remote? Touching the joystick should let you control the drone as it interrupts the mission.
Yes. However there was no respond when i tried to regain the control and it was moving at a fast speed at the point when i tried to regain the control
It is quite unexpected as the remote controller should always respond to pilot intervention. I would suggest to DJI support as I am sure they will provide you more information.
can you roughly tell me what is the cause of the sudden movement of the drone?
There can be many reasons. For instance, the fail safe actions can trigger automatic piloting of the drone for landing if the signal is lost and if the battery is too low. Let us know any update from DJI.