Not happy with service

I went to look at and test drive a car which I was interested in at the JHB South branch and completed the finance application. I was told the process is really quick. When I arrived at home I received WhatsApp messages to say my application was approved and that someone would contact me during business hours. The next day I haven't heard from the finance person yet and decided to phone the person working on my account. When she answered she told me that she was not logged in and would phone back in 10 minutes which never happened. The next day I tried phoning again with difficulty to get through. After eventually getting through I was told that my application was approved and what my payments will be, also that the offer to purchase would be sent via email. When I received the offer to purchase I noticed that a warranty was added as well as a tracking device, license fees and delivery fees. When I queried the warranty I was told it is compulsory. I then asked if I cannot rather change this to a manufacturers warranty that can be added to the offer to purchase and was told that it cannot be done and that I need to get the warranty myself which I would then need to purchase myself. Once it is purchased I need to send proof of the warranty to We Buy Cars and head office will check if the cover is the same as the warranty they want to add, if not they will not release the car and I still need to take the one they added. Why can one not get a manufactures warranty and why is the one from We Buy Cars the only option?