I would say sign up for an account on the IRS website and check your balances. If the payments appear in your account then it should get corrected in time. If one or both payments are missing, then all I can suggest is to try to get the Tax Assistance Service to help you locate the missing funds. The US treasury cashes the checks and does ACH transfers but they have to report this accurately to the IRS. If they fail to do this, then the IRS is clueless and can't do anything about it.
