Can someone help me?

I filed a claim with my insurance company for storm damage to my fence and roof. The initial repair estimate from the insurance was around $20,000, but I found a contractor who could do the work for less. After the repairs, the total invoice was about $16,837. The insurance sent an initial check for $10,000, and I was told that the depreciation check would be $4,000. After months of sending documents and waiting, they calculated the depreciation check to be only $400. They based this on my contractor's invoice total instead of their original $20,000 estimate, leaving me $6,487 short. I don’t have the funds to cover this.

Is there anything I can do in this situation? Any advice would be appreciated.