STH,
that letter would certainly attract immediate attention! I've already advised one of the troops on the Sqn I work on to pop into OC Admin office and state that JPA was causing him financial hardship after a lack of payments from good old JPA. Worked a treat as he was issued with a cheque before COP that day.
Ridiculous that you have to go to those levels however, the bottom line is that nobody else can help you, not even the Chief Clerk...