"I am currently in default on my mortgage.  I have been paying premiums to a private mortgage insurer for 6 years, is there any way these premium dollars can be applied to my mortgage payment?"

 Mortgage insurance protects the lender, not the borrower, and you have no legal claim on the premiums you have paid. However, your insurer is on the hook for losses if your default ends in foreclosure, which means that they have a financial interest in preventing this from happening. All the insurers have programs under which they will assist borrowers in distress who they believe can avoid foreclosure with their help. If it costs them less to prevent a  foreclosure than it would if the foreclosure occurred, it is in their interest to help. Contact your insurer ASAP.