They have not altered any thing. They can just sale to any walk in customer that is willing to pay them OWN money and they rebook the car with your name again which will come in September/October. Do note the invoice number shown on Indus website and the actual one you will get when they handover car to you.
Few years ago this practice was very common but now Indus has done steps to inform actual buyer such as sending SMS to stop dealerships doing that. Mostly dealerships just want to make money and they can do anything.
Do contact Indus helpline and explain your case that your car is not traceable. They will surely help you out.