How can we get unused time cost on any subscription in laravel cashier?

This is invoice of stripe subscription that i have creat

$business->businessCashier->findInvoice($id);

Above code i am using to retrieve invoice. But i want the unused time cost to show the same on checkout page. Can anyone please help me in retrieving unused time when we are going to swap our subscription so that we can create a view so user will know how much amount he has to pay.

I am creating a checkout page where i have to use this unused price.

via Chebli Mohamed