Hyundai i20

I bought a second hand Hyundai i20 last year 31 July 2015 at investment cars , I was told the car was still new and I won't experience any problems . Simon also told me that the battery was new. Few weeks after purchasin the car: my grandfather told me that my spare wheel and front wheel are not okay so we took it back to investment cars and they assisted us and gave me 2 new ones . today is 6months since I had the car for the past 3days I haven't been to work due to this car . I called Hyundai to come assist me with the car only to find out that it's a battery issue sent emails to Simon and I did not get any assistance today I went to battery centre in Midrand and I was told that I was given an old battery and I must take it with my dealer I drove to investment cars and Simon did not even assisted me he just told me that I should wait for the finance guy who told me that they do not cover the battery ,I also told him that Simon told me in July that the battery was new when I purchased the carhe just looked at me and said there's nothing he can do. Hello Peter kindly assist .