Resignation

You just need to resign officially and get a copy of your resignation form with any receiving acknowledgement way.
If your company has electronic resignation system then it is a way better as you will receive a confirmation email.
If they rejected your resignation resubmit it.
Try to have a proof once they ask for money then go and file a complain in the nearest labor's office and they will release you with no issue.
I have posted also the labor law today, read part V of it.

Thanks for Reply.
regarding labor office complaint, shall i know how much time will take to resolve my case. cause i want to go back my home as early as possible.
also is it offer letter is valid after signing the Employment contract cause in my offer letter they mentioned that if i want to go back prior to complete the contract then i have to pay the visa charges and all relevant charge incurred for my employment.


Regards,
Eknath

There is no time frame for such thing, in similar cases they take action very fast.
For the Visa charges, it is employer responsibility to pay for Visa charges as per the law in KSA, they can't ask you to pay even if it is mentioned in the offer letter.
Again, please read the Labor Law, it is very important to know your rights before you file a complain.

Regards,
Osama.

Thank you very very much for your valuable response.

you are welcome