Remote employer refuses to approve my vacation

Question

This is my first time posting here so I will try to be brief and to the point:
I worked in the current company for year and a half.
They are stationed in USA, but I work for them from Serbia.

I resigned from service on January 18th 2021 and asked to use remaining vacation days.
My last day is February 16th.
It is important to point out that I have 12,5 vacation days and all of my work is finished.

Both February 15th and 16th are national holidays so Serbian office will not work during those days
I wanted to merge my vacation days with the national holidays, so I asked to use vacation from January 28th.
Theoretically, I would "return" to work on February 15th, but Serbian office will be closed, so after I leave on January 28th I will actually be gone for good.

I have sent an email, asking for vacation approval on January 15th to American line manager, Serbian office and HR.
Since then I haven't received any response. A team member told me they might force me to shift my vacation starting date from January 28th to February 1st, explaining that Serbian national holidays still count as working days, regardless that Serbian office will be closed.

American team also started assigning me various **newly created** jobs that are not under my jurisdiction and would require me to not use any days of my vacation in order to have a theoretical chance to finish them.

They tried to do this to my former Serbian colleague who left the company as well.

EDIT:

I have turned to Serbian manager, and it turned out they can not force me to deduct 2 days of my vacation as described above since they can get sued.
I have forwarded the email to USA manager and USA HR but still they ignore me.

QUESTIONS:

I feel like they retaliate, and do not know what can I do to protect myself from getting assigned newly created tasks, and force them to allow me to use my legal right to use my vacation.
Their unofficial say that I need to use (LAST WORKING DAY - 12 days) date as a start for my vacation sounds illegal to me and I feel robbed of 2 days of my vacation. What steps must I take to be able to use my vacation as described above? I do not want to allow them to tell me when to use my vacation as I feel that should be my decision since I have finished all of my work and documented everything for my replacement.

Please, please, please help as my time is running out fast (28th January is next Thursday).

I apologize if I tagged the question wrong, this is my first post here.

Answer 1

I do not know the Serbian law but from my experience working in different countries usually companies could refuse to give you holidays. If your contract ends and you did not use them, they will simply pay them to you in your last salary.

You should check your contract, but I imagine that this is something highly likely.

It has happened to me, it sucks, but you get more money; however, there is still the chance to speak to your boss and kindly ask to have the holidays approved at least the 2 days you seem more interested in.

Answer 2

I'm also from one of the ex Yougoslav republics and I'm I a similar position as you; working for a local company owned by a foreign company (although not a USA one). Talking to my Serbian coworkers, it seems the Serbian work laws and customs are very similar to my country's.

I can tell you that the USA manager has no say in when your holidays are. If a day is deemed as a non-work holiday by the Serbian government you either get the day off or the company needs to inform you in advance and pay you extra to work on that day (I think the factor is 1.5 to 2 times the regular salary).

I cannot talk about the legality, but it is also highly irregular for a company to prevent the worker from taking the rest of the vacation days when leaving the company.

If they haven't answered yet, I'd definitely go personally to the HR to clear up the situation. They are the ones that know the local law and can keep your manager in line.