URGENT!!!!! WORK PERMIT B APPLICATION

Hi all,
my girlfriend is non EU citizen of Serbia, she has been here in BRX for 5 month now with a visa D as a trainee at EU commission, her permit expires on March 1st.
She has now found a company that would like to sponsor her and do the process for the work permit B Highly Skilld Special Categories.
We have been in the office of strangers and they said to bring the contract before march 1st so they will forward it to the ministry for the approval, and to request the change of status, they have also said that she doesn't need to leave the country by march 1st but she has to pay 200something euros for the change of status, and to the question 'can she work meanwhile starting from march 1st? they said yes, she can work.
But my doubt is, how can she work if the work permit has not been approved yet? and which is the start date that should be written in the contract?
We have asked other administrations whether she can start working and they all said she can't, why the office of strangers says that she can? are they really giving false information to the ppl? such important information? you can potentially face legal issues if you work without permit, are they really that crazy???

I dont know if there is any exception but normally you can't work before having the work permit. It is actually emphasized that the starting date cannot be before the approval,so there should be a clause in the contract that the official starting date will be after having the approval even if the date in the contract is different.

She can always work as self-employed person in whole EU !

Ideally the WP B is applied for by the company itself (by HR) which includes the contract, their documents, your girlfriends' health certificate, etc  and when the permit arrives in the cityhall they contact the HR who picks it up and gives it to you with which you apply for the residence card A based on that WP B. But of course, she cannot work for that new employer till the wp B is approved and received.

The Change of status fees has increased recently and will keep increasing for different types of permits and COS applications.

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