Here is a simple approach in up to 4 steps:
0 - Advise the team you are going to fix the repository
Connect with the team and let them know of the upcoming changes.
1 - Remove the last commit
Assuming your target branch is master:
$ git checkout master # move to the target branch
$ git reset --hard HEAD^ # remove the last commit
$ git push -f # push to fix the remote
At this point you are done if you are working alone.
2 - Fix your teammate's local repositories
On your teammate's:
$ git checkout master # move to the target branch
$ git fetch # update the local references but do not merge
$ git reset --hard origin/master # match the newly fetched remote state
If your teammate had no new commits, you are done at this point and you should be in sync.
3 - Bringing back lost commits
Let's say a teammate had a new and unpublished commit that were lost in this process.
$ git reflog # find the new commit hash
$ git cherry-pick <commit_hash>
Do this for as many commits as necessary.
I have successfully used this approach many times. It requires a team effort to make sure everything is synchronized.