Processing the check is IRS's responsibility. If they accepted your check, but do not process it, it is their fault. Once they accept your check, your end of the deal has ended. A while back, I got a notice that I did not pay my state tax.
1 The xiphoid process (Latin: processes xiphoideus) is a small triangular cartilaginous extension of the breastbone.
replied May 8th, 2012. It is very common for persons to become aware of the xiphoid process, and pressing on it makes it tender. So don't press on it - usually ignoring it leads to comfort and mental relief. If you continue to think that the xiphoid process is enlarged, then you will need to have a physician check it.