Misplaced my gate remote and house key

I rented a car at the Sandton branch on the 1st September and returned it on the 2nd September and forgot my gate and house keys inside the car.I called on the Monday and I spoke to a lady (coloured accent) who said she found it and would keep it safe for me.As I was travelling the past 2 weeks I went there today to pick it up and they can't find it any where even in the lost and found bin.

I'am very upset and consider this blatant theft.So one can't forget ANYTHING in the rented vehicle without it being ******?