I am not aware of a requirement in Reg B or Z for the customer to sign a written acknowledgement indicating receipt of the appraisal(s). Did the auditor provide a citation that would give me more insight as to what they found? Do you document your file to show when the appraisal(s) was given? Do you have written procedures for ensuring you comply with the delivery requirements?
Was this a listed as recommendation or an actual violation of law/reg?