Complaining about BB nissan sinoville

I have received a very BAD BAD service, after taking my car for a service and I was given a very pathetic attitude by the lady assisting me, after they made my car not to start as it has locked, she told me to make other arrangements for my daily meets as there is nothing she can do to fix the mistake they made, and refused to call the manager for me as i needed a way forward, and no one even bothered to apologize for the mistake they made, and the lady was approaching white people in a good way but very rude towards blacks, i will never set my foot at Nissan sinoville never ever.