Acceptance of offer rejected by future employer

I went to the interview on the third week of April 2017 at Company G. I'm being interviewed by one of the company director himself. The interview process went through smoothly and I am being offered orally a certain amount of salary, upon confirmation will have additional increment etc including other benefits by the director himself. 

When he offered me, I told the director I will provide him an answer 6 days later (with date specified) orally. During the course of 6 days the director did not rescind his offer. 5 days later I called the director to informed him I accept his offer, and enquired when and how to formalise the agreement.

He asked me to contact the HR which in turn asked me to send her the academic transcripts and necessary certificates. I duly did. Subsequently when I followed up with the director, I am told they could not offer me the position due to my academic not looking good.

From the above did Company G violate any laws?

As you did not do a voice recording of the verbal offer,
it would be impossible to prove that a firm job offer was made in a Court of law.
So you are out of luck.

Even if you could prove there was offer and acceptance, there is still another problem. In my opinion, there is no consideration on your part as you had yet to commence employment. As such, it would be difficult for you to obtain any meaningful remedy.