All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu 'alayhi wa sallam, is His slave and Messenger.
The question is somewhat unclear, nevertheless the permissibility of taking this allowance depends on the condition. If it was conditional upon carrying out the audit and you did not do it at all, then you have no right to it. However, if you did perform it, without it being related to the benefits or the like, then you are entitled to what corresponds to the work you actually did. Hence, you should contact the office you work at, inform them of the actual situation, and verify what portion of the allowance you are entitled to and what portion you are not.
Allah knows best.