Promise not kept

I contacted Discovery as I wanted to take on a new policy for my car. I was quoted 'R1174 when I told them I have my own car tracking system installed and couldn't take the discovery one they increased my premium by R75 which I advised the Sales consultant Arthur wasn't fair and he advised that he agrees with me and he will take it up with the Retention department. HE ASSURED me that it was a small amount and HE IS SURE that they will grant the reduction. He asked that I take the policy and that the next day he will give me a call together with the retention guys to sort the matter out. I wasn't contacted the next day and I had to send him an email a couple of days later to remind him. I was then given a call by the Retention department and was advised that they cannot reduce the premium by the R75 that was promised to me. I took on the policy on the basis that I was assured that the R75 would be taken off my premium of which now because the policy is in the books they tell me they cant. <br> <br> I feel like I was mislead in taking this policy on false pretence. I need somebody to give a call urgently.