22 CFR § 513.225 - Failure to adhere to restrictions.
(a) Except as permitted under § 513.215 or § 513.220, a participant shall not knowingly do business under a covered transaction with a person who is—
(1) Debarred or suspended;
(2) Proposed for debarment under 48 CFR part 9, subpart 9.4; or
(3) Ineligible for or voluntarily excluded from the covered transaction.
(b) Violation of the restriction under paragraph (a) of this section may result in disallowance of costs, annulment or termination of award, issuance of a stop work order, debarment or suspension, or other remedies as appropriate.
(c) A participant may rely upon the certification of a prospective participant in a lower tier covered transaction that it and its principals are not debarred, suspended, proposed for debarment under 48 CFR part 9, subpart 9.4, ineligible, or voluntarily excluded from the covered transaction (See appendix B of these regulations), unless it knows that the certification is erroneous. An agency has the burden of proof that a participant did knowingly do business with a person that filed an erroneous certification.