Regain the files lost due to Git reset --hard

I have a remote branch, that I seem to have messed up. Here is a sequence of steps that took place in the chronological order:

• I had made a few commits on it, lets call my latest commit as Commit #4 for simplicity
• One of my teammates pushed Commit #5, that I wasn't aware of
• I started working on the next steps and pushed another commit. However, I should have pulled the changes on my local before doing so (My first mistake)
• Sooner I pushed my changes there was a Commit #6 consisting my code changes and an additional Commit #7 the merge commit. This Commit #7 reverted all the code changes performed by my colleague in Commit #5 (I don't know why this happened; as my colleague's commits were in an entirely different set of files)
• I made a git revert on Commit #7, which Git didn't allow (as it was a merge commit). So I made git revert on Commit #6 and voila, all good! This is Commit #8 now, where the head is pointed

So this is how my commit history looked like, at this point:

• Commit #8: Revert Commit #6 <- HEAD
• Commit #7: The Merge Commit (that reverted my colleague's changes done in Commit #5)
• Commit #6: My changes over Commit #4 (since I missed pulling before my code changes)
• Commit #5: My Colleague's changes
• Commit #4: Base

Now, this is where I commited a BLUNDER!

I got into the greed of clearing up the mess in the Git History. So I executed these commands:

• git reset --hard <hash for Commit #5>
• git push -f

I expected the HEAD to point to Commit #5, from where I could start afresh

However, this is what my commit history looks like now:
Commit #6: My changes over Commit #4 (since I missed pulling before my code changes)
Commit #4: Base

Commit #5, my colleague's changes are GONE! :'(

I totally understand that git reset --hard is one command that needs to be executed with a lot of responsibility

Is there any hope of getting the Commit #5 changes back?

• I checked with my other colleagues to see if they have a copy of Commit #5, so that atleast we have a reference to replicate the changes. Unfortunately none of them had pulled the latest updates after commit #5

• The colleague who had authored the changes in Commit #5 will certainly have it on his local repo, but he has gone on a week long vacation

• Checked official Git documentation, but it says there is no way of reversal once git reset --hard is executed

• Checked git reflog, as expected, nothing found there

As long as a commit was created with your files, git never deletes the files from its store unless you ask it to with git gc (don't do this now!).

Are you sure there's nothing on git reflog? You should definitely be able to get back to at least #8 with reflog, from which you can find #5. You can also try git fsck --lost-found which will list you any commits which exist in git's store but are not part of any ref's history.