Just Recently bought a house, rent to own furnace ...

Just Recently bought a house, rent to own furnace was overlooked in agreement. I can t let the elderly man pay it all. This company won t even negotiate with me on a reasonable buy out price for furnace. I looked it up a $4000 furnace installed has a buy out price of almost $7,000 furnace price when financed is over $12,000. Be careful the contract you sign with them will end up costing you many times what the furnace and installation are worth.
Wayne the manager wont even return my call.
Not very good customer service