Graduates from foreign University and working permit in Vietnam

Hi Leah Hye Ryeong LEE.
Welcome to the forum!

The entire responsibly to justify your legitimate employment in Vietnam to the Labour Dept. lies with your employer, not you.

As a foreign professional (industry worker) in VN, you are expected to have at least 3-5 years of professional experience and relevant training/s in the same field.

TBH, sometimes a 5 years worth of documented experience can override the requirement of a 4-yr degree, provided you have relevant industry training.
Least likely that it will happen the other way around.

The resort that wants to hire you is well aware that you are a fresh graduate without any experience.
It's now up to them to convince the VN officials that your valued degree (from a Western university) and relevant industry trainings (if any) make you more "skilled" than a local with equivalent degree/diploma from a VN university and a few years worth of experience in the same field.

I have been calling to immigration offices if the company can basically issue me an invitation letter that they would like to hire you to replace 3 years working experience with my Bachelor's degree but it is still not clear.

That's what the company should be doing, not you.

My suggestion is, just ask the company to arrange it for you (if they can) within a certain period of time.
Else, don't waste your time, start looking for other suitable opportunities elsewhere, may be in Europe since you've studied there.

Stay informed, it's illegal to work in Vietnam for more than 3 months without a valid Work Permit.
In those initial 3 months one needs to be on a sponsored B-visa. I reckon that's what you are after at the moment.

Hope this info helps.
Good luck!