Litton Loan Servicing Charging me for "forced insurance" when I have provided documentation 5 times that my property insurance has been in place continuously since I bought the property in 2006 Houston, Texas

Since last year, Litton has been sending me notices that my property insurance has lapsed. My insurance company and I have sent documentation 5 times verifying that my property insurance is in force, and has never lapsed.

For the November payment they showed a negative escrow balance for the "forced insurance".  I have talked to representatives in the insurance department and customer service on numerous occasions and still has not been resolved.  I wrote to the president, Larry Linton, November 15, but have not yet heard from him.