Your question seems to answer itself. You have tried twice and were denied. Do you really think they will waive the fee without any paperwork? Generally, an offer in compromise is only accepted if you prove you will be unable to pay the full amount. The offer is not a way to just pay less because you don't like the tax and penalties assessed.
If there were errors on calculating your disposable income, perhaps help from a professional would help. That depends on the chance of Offer acceptance ant the amount in dispute.
I hope this helps.
Steven A. Leahy
Please note that the above is not intended as legal advice, it is for educational purposes only. No attorney-client relationship is created or is intended to be created hereby. You should contact a local attorney to discuss and to obtain legal advice.