Property Taxes

[James Sullivan]

 Is there a way that I can dispute a property tax assessment? A rental property that I have came back with a market value of $81,500 and $815 due at the end of the year. This property appraised for only 65K just like 5 months ago. 

1) Why are the values so much different? 

2) How can i dispute the market value with the appraised value and is there a way to pay the taxes based on the appraised value?

3) If I can't use the appraised value with the county can I try to refinance the property based on the market value?