It's the company which because "who" is for a person, "which" is for a thing. Companies are things, not people.
It sounds better to use "that". For example: The company that polluted the river was ordered to clean it out within two years.
"That was wrong" is a grammatically correct sentence.
Yes, it is grammatically correct.
Yes, Almighty God is grammatically correct.
This sentence is grammatically correct.
No, it is not grammatically correct. If you want someone to correct it for you, please can you explain what you are trying to refer to?
My company has entered into.....
Group of companies is grammatically correct.
The correct phrase is "went out with the company of your friends." This construction conveys the idea that the friends accompanied you.
If you use "with" it indicates there's a company of friends and you went with them. If you use "in" it indicates you are part of the company.
"Not like that" can be grammatically correct, depending on the context.
Yes! That is grammatically correct!
Yes, 'for free', is grammatically correct.
The phrase "You are not knowing" is not grammatically correct. Instead, you can use "You do not know" or "You are not aware."
Yes, Almighty God is grammatically correct.
"That was wrong" is a grammatically correct sentence.
Yes, it is grammatically correct.
'What a drunkard you are' is a grammatically correct English sentence.