Car Extended Warranty

Last year I purchased a second hand Kia

Advised it had Four years left of Kia Warranty

Got a email advising me that the car needs to be Serviced. As unless the car has a annual Service Warranty is invalidated

Not advised of that when I purchased the Car

Choice keep paying many hundreds for annual Services, regardless of low mileage                   Or loose extended Warranty  ?

Looking a Warranty document

Think it will be a case of giving up extended Warranty