Go to Hanoi they will give you that’s what I did ,they denied one in hochimin and the next day I took a bus to Hanoi submitted and picked my visa the following day .They don’t have that system to check if you had applied in Hochimin
The work permit I submitted isn't valid it's for the previous school and the Non B visa I got from there is for my new school.They want to see if you have been working there legally