Which sentence is correct?

Sentence 1 is correct.
the assistance of my friends = 朋友的協助
But for the assistance of my friends , I might have been helpless.
如果唔係得朋友既協助我會好無助。

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Both sentences are wrong.

Try this:

Without the assistance of my friends, I might have been helpless.

Sentence 1.

Sentence 2 唔make sense. 特別係 ＂my friends of the assistance＂ 意思是協助的朋友. Sentence 1 ＂assistance of my friends＂ 朋友的協助　先至岩.

sentence 1 will be correct.

But sentence will correct if the word 'assistance' change to verb
whatever, the one that i think it should be correct is sentence one

This is correct 2.But for my friends of the assistance , I might have been helples.