The legal implications of withdrawing from a job offer

Hi Mr Hari,

I have confusion over my decision after accepting one job offer from a company in Abu Dhabi. I accepted it and signed the initial offer letter on 14th Sept. Then I resigned and currently serving the notice period.

At the same time, now after working unofficially with a new company (A) for few days, I came to know that the new company (A) is not matching my profile and the project I am hired for is delayed.

I have a company (B) offering a job and wants to discuss the offer and joining date, company (B) is better for me. I went through all the T&Cs mentioned and signed a contract.

It is mentioned that "Unlimited Period: Either party may terminate the contract by giving a 30-day written notice to the other".

I am still serving the notice period and I want to apologize and turn down the offer from the company (A). Is it ethical?

Is it possible to make such a decision as I am sure I am not going to enjoy my work in the company (A)?

Can the company (A) make any legal problem for me?

Kindly advise.

Regards,

D.