Bad service in overall

I woudnt recommend anyone that doesn’t have experience with cars to purchase at Vw Mastercars . I collected my golf 7 on the 3rd of Dec 2024. Jan 3rd 2025 my car broke down I was given so many excuses as to what happend and up till today I’m not sure why was the cause of my car breaking down . Car was at the dealership for few weeks and I eventually got the car back then I noticed the car spare don’t work on the car I have contacted the sales person Shaheen Toyer explaining the key don’t work he has then explained it will b sorted everyday since I have messaged and called and today is the 10th or march and no key had been replaced fixed or coded . After sales assistance is bad they over promise and under deliver I’ve required for a new sales agent and even that cannot be done. What do I do in this case where I am not taken seriously ????