If the seller still owns the property, then they have a right to refuse your offer. Long term, it may not be in their best interest but they are entitled to it nonetheless.
At this point you can either wait for the property to go thru foreclosure and the bank list it for sell or move on to another property.
Either way good luck
Grit you teeth and walk.
There may be many other reasons your offer was not accepted besides the price.
Even with a cooperative seller, the odds of success are 30% or less.
Let the listing agent do their work and if this can not be salvaged, find yourself another Chesterton home to buy.
Best of success to you,