Is this paragraph phrased correctly?

[motico]

Is this paragraph phrased correctly? (Especially the conditional)

If you really engaged in fighting wrongdoings in the company (which nobody can deny their existence), many would joined you. But the unpleasant fact is that you are taking part in a campaign which aims at discrediting our company's reputation.

[Gillnetter]

Is this paragraph phrased correctly? (Especially the conditional)

If you really engaged in fighting wrongdoings in the company (which nobody can deny their existence), many would joined you. But the unpleasant fact is that you are taking part in a campaign which aims at discrediting our company's reputation.

If you really engaged in fighting wrongdoings in the company (which nobody can deny their existence), many would join you. But the unpleasant fact is that you are taking part in a campaign which aims at discrediting our company's reputation.

Joined is the past tense of join. The text is not written in the past tense, so "joined" is incorrect.

(which nobody can deny their existence) Which no one can deny that they exist.

[Tdol]

(which nobody can deny their existence)- How about (and nobody denies that they exist)