Ratification Concern

Advice requested for the following ratification issue...

1. Unauthorized commitment occurred for commercial services above micro-purchase threshold.
2. The Government Agency began the process to ratify IAW FAR 1.602-3.
3. The ratification process required significant fact gathering causing delays.
4. The Contractor became frustrated with these delays and sent an email stating that they no longer wished to pursue the matter and considered it closed. In other words, they did not wish to be compensated for the work performed.
5. After this email the contractor became unresponsive to government emails and phone calls.
6. Our Judge Advocate advised we request a “Release of Claims” from the contractor to make certain they do make a claim against the government including interest at some future point in time.
7. The contracting officer disagrees with processing a “Release of Claims” believing it to be unnecessary because there is no contract against which to apply the Release of Claims clause:
   1. FAR 52.212-4 (Alternate I) (i)(7)
   2. FAR 4.804-2 (a)
8. The contractor subsequently did not renew their registration in the SAM so even if ratification was processed the contractor would not have the ability to be made whole without being registered in SAM. FAR 4.1102

Concern/Questions:

1. Could the vendor at a future point in time make a claim and the government be held liable for the work performed including interest?
2. Would a release of claims make certain this does not happen? Would it be necessary considering the email and the fact that the vendor is no longer registered in SAM? Or should we close the issue?
3. What am I missing? Are there any other solutions?