I wonder of you can persue legal action regarding them if the seller refuses to refund as They say it's not thier fault.
Especially following the necropsy and final diagnosis. I'm fairly certain the vet who had seen them can confirm the illness was too advanced to be something you had done and that they were sent to you carrying this disease
I'm sorry you had to go through this. Sometimes that final closure is needed. As well as the peace of mind that it isn't something to worry about with your other noodles.