Are they requiring a certified audit; or, an audit? There is a difference.
If not requiring a certified audit, then if any LPAs exist in your state anymore (Licensed Practical Accountants - they are a dying group, if not all ready extinct) they could do an "audit", but not necessarily a certified audit.
If needing a certified audit, as far as I'm aware, only a CPA can do that. Why won't the CPAs do an audit if you pay for it? Perhaps you'll have to try a regional firm? Single office or small office....I guess if they won't do it for a fee I don't know of a solution.
Good luck