Difficult one, but happens fairly often when buying a car which has. Long lead time.
whilst it may have been a dealbreaker for you, unless you specifically wrote in your order that this shoukd be fitted or contract is void, the law is on the manufacturers side as it specifically states “specifications are subject to change”
a car being built to a spec on line, cannot be retrofitted easily free build, wiring harnesses for example, may not have the wiring for this particular specification, and retrofitted parts may not be available, there are only a few things that a dealer can add.
as has been said for eons, “buyer beware”
you may get a sympathetic response from Motability, or it’s a battery operated heater and cooling fan that you will have to manually use.
im assuming the car is a diesel, as my petrol car heats up or cools down within 2 miles of starting it up