program for stoping the motor with the feedback of Hall Sensor

The problem is in the query. You are querying a feedback, rather than the actual count.

Since the command is telling the motor to spin in reverse, then the count will be negative. Therefore the motor in a sense won't stop, or won't stop unless it reaches position first.

If you are doing this based on the hall sensor count, then you query via the following command.

count = getvalue(_CB, 1)

Since you are going negative count, then the second argument looking for 10 should be -10 if you want it to go back to 0, unless for some reason the counter is counting positive for whatever reason.

if count < 10

That is because the go command is a motor command for output %. If you want to go to a specific count, then you need to use the closed loop count position and use setcommand(_P, 1, value).

If it stalls, then something occurred to create the stall condition. You can cancel out the stall condition by doing the following. Setting the motor mode back to open loop, and sending the motor command to 0.