Poor service

I bought a "new" audi Rs3 from audi centre menlyn in December, took delivery of the vehicle on the 29th of December, so i recently enquired as to the duration of the warranty and service plans at my local dealer, and to my surprise it shows warranty already started in August 2023, now in all my history of owning new audis the warranty and freeway plan is supposed to start on the day you take delivery, i brought this to the attention of the salesmen and subsequently to audi south-africa aswell, the dealer solution was to type me an email stating that they will extend the warranty on the last year of ownership of the car. Here is my problem dealerships are frequently changing staff members, what if i get to the dealership after 5yrs and show them this agreement and they say they aren't aware of this agreement as the person i agreed with is no longer working there. Also i have a previous audi Rs3 which the warranty expired in 2022 May i came to the dealership unaware that the warranty expired and wanted to claim a light that was turning yellow on the LED in June 2022 and audi simply told me warranty had expired. Audi is robbing me of 4months of warranty time whereas they turned me away cause of a warranty that expired a month ago I'm not getting any assistance regarding this matter this is the 5th Audi I'm owning and as an old client im truly dissapointed with the service.