Enpure Home Comfort

Its been over a month that i tried at all levels to amicably settle my case with Enpure amicably and with appropriate reasoning and using a notional approach. Unfortunately, all my effort went in-vain and now a days, i'm not getting any response to my emails from Enpure. Iterating my story with a hope that it will be resolved
40 gallon GSW hot water tank was contracted and installed on mid-Sep, 2012 for 120 months at a price of $13.99/month with annual rise of 3% to rental fees. no payment defaults till date. The contract model has serial # S0305xxxxxx and i've learned that it's tank manufactured in May 2003. below are my questions

1. How much more life is left in this old tank? I believe that year of manufacturing would play a role while determining the life left in the tank
2. Based on the life left in the tank, I would request for final buy-out price based on depreciated fair market retail value of the equipment on a straight line basis in accordance with generally accepted accounting principles
3. Per contract, there is no price mentioned to remove the old unit after its agreement period i.e. Sep 2022. Should the customer even pay any amount to get the equipment removed from the house? and how much? and who will determine the amount incl account closure?

Pl note: I've learned that there had been no service done in the hot water tank after it was installed in my house and the anode rod has not been replaced too.