Frustrated and Appalled

On 16 July I went to pour petrol at Engen in Soshanguve block L and the petrol attendant asked if theres anything else he can check on my car. I asked him to check the water tank, he poured a little water and then did not put the cap back on and I drove off thinking all is well. The next day before I left for work I did a pre trip inspection only to find out that my cap was missing. I went back to the peteol station and the Manager took me from pilar to post and said that the cap was replaceable, however this could cause serious mechanical issues to my car which has inconvenienced me so much because i had to order a new cap and in the mean time find other dangerous alternatives to cover my tank. I'm distressed due to the incompetance of your employee! I've contacted the head office and spoke to someone who said they'll send an email that I should respond to, but guess what??? I'M STILL WAITING!!! I'm appalled by this and utterly disapointed! I redress and want this to be looked into!