Unhappy bad service

Bought a vehicle at Human Select less than a month ago and found a problem with it going on holiday took it back early January salesperson was on leave had to wait he made a booking took it in and they let me know after a few days only it's the Injectors they I received a mail from innovation they want to claim the Injectors on the extended warranty Im paying for my peace of mind .....I'm not happy with that cause haven't had the vehicle long les than a week and now they claimed Injectors on my extended warranty and they vehicles is still having the same issues i reported now I must wait again because they to busy and must make a booking again the first time I thought i had a booking but when the vehicle arrived they only made booking and the vehicle had to wait for the booking date then they only ordered the parts after the claim process and it was all for nothing and now again and now I can't claim for Injectors again it was replaced unnecessary because it didn't solve the problem I told him and someone from management I'm unhappy with this and I want another vehicles wich is my right...but they didn't respond yet