None of the AIA exceptions would permit you to enjoin the IRS from action, or force the Service to act. The exceptions are all based upon direct injuries concerning wrongful levies, and you are not directly injured here -- because you have not been able to prove that the Service must collect the tax.
Regardless, the Sebelius
case shows that the AIA can be avoided entirely, if the activities complained about do not prevent the IRS from lawfully collecting taxes. To me, that would permit a lawsuit against the IRS for a writ of mandamus
, so as to force it to do its job, and collect taxes lawfully owed.
This would also, in my opinion, avoid the issue of whether or not the IRS must investigate your whistleblower complaint -- because it's pretty obvious that if there is a lot of tax money at issue, then the IRS is plainly not doing its job by refusing to collect that tax money.
Note: I am not going to comment on the validity of your underlying legal theory, re health care providers and insurers/health care plans. But, I can see how the AIA could be avoided, assuming you can prove to the district court that taxes are due from some taxpayer or class of taxpayers, and the IRS is refusing to collect those taxes, for no rational purpose.
Hope this helps.