Export of service without BRC and Agreement

Supplier has declared Rs 65 lk export of service,and showing bill (which is unclear as HSN is related to other service) and LUT only.supplier has not availed ITC, so as neither availing tax or liability generated.Also not showing any agreement not telling anything about transaction on pretext that fire broke recently so all records burnt Bank statement also showing payment received prior to raising bill .Matter is raised by Audit authority.How to deal such transaction ,