As ELTel says, you cannot get a car that they aren’t making any more. But it sounds to me like you have a perfect case for twisting their arm to get some sort of concession from them for keeping you hanging, especially as Motability sent you a holding email every fortnight. Keep banging their heads together and asking both parties what they are going to do for you to sort out a mess that is no fault of your own!
I’ve read about this happening for several different manufacturers though, its not exclusively a Volvo thing.