One wrote:

No one has ascended into heaven before Jesus - John 3:13 Elijah ascended into heaven - 2 Kings 2:11

Only one may be correct as they are mutually exclusive. Which one?

Athanasius responded:

The Orthodox teach that there are a number of heavens.

First.

The heavens where the birds fly

Second.

The heaven of the stars.

Third.

The heaven where God dwells.

Fourth

Paradise where the saints and martyrs are which is before the throne of God (the portico of heaven as it were)

Fifth

God's presence.

As regarding Elijah it is quite possible that he (and St john)

ascended to Paradise/heaven but not into the Holy City, nor the very presence of God. It is believed Christ's words about His ascension related to Himself within the Divine Essence and thus the dwelling place of God's Throne and God Himself. This can be seen by the extra statement that jesus said..."No one has ascended into heaven EXCEPT the Son of Man who IS IN HEAVEN" jesus was standing on the earth at that very moment Hem claimed to be also in heaven at the very same time. (Only His Divinity explains this).

From this perspective there is no discrepancy.