You may want to ask a moderator to move this question to the mortgage forum. Your question isn't really about FICO scoring, but about how VA loans and lenders work.
I am no expert there, but as far as I can tell, they have asked you to call the company handling the mobile home debt. You don't want to, because you know they will not say what the VA lender wants to hear. The answer would seem to be, "No they will not approve you unless you call, because they have told they won't." But I may be missing something.
Anyway, there are lenders who hang out in the mortgage forum and they may be able to advise you.
The requirment for a current letter stating status is most likely a requirement that will not be satisfied by simple reference to your credit report.
The fact that the creditor sold the mobile home does not mean they had no loss, and thus that you have no remaining debt.
What is the net debt remaining after deduction of the recovery price from the loan balance?
That may not have been properly updated in your credit report, and is likely what your mortgage underwriter wants to know from the creditor.
That info could only come from the prior mortgage holder, as they did the transaction.