Radio malfunctioning not attended by Ford

I bought the new Ford Ranger on 20/04/2016 brand new. It came with factory fitted aircon and radio. Somewhere during August the Aircon started to malfunction; it was fixed at no cost on 12 September 2018. On Tuesday 29 January 2019 the radio also malfunctioned; I booked it in but was told that i need to pay upfront R914 for testing and then i will be billed for the repairs. I find this strange and let alone unfair both the AirCon and the Radio are factory fitted and are not part of the exclusion on the warranty; which expires after 4 years i.e. 19/04/2020 or after 120 000km whichever comes first. The odometer on the car is on 92319; which means I am still within the warranty. Now why must I be paying for this service to fix the Radio. Both the Radio and AirCon are part of Audio system on the book provided. I spoke to Kagiso from Ford Call Centre and ms malaza from Ford Dealership in Gezina