Gillette Razor Blades Sensor 3

My girlfriend bought me Gillette Sensor 3 razor blades by mistake, I have a mach 3. Unfortunately I had opened them already. I went back to buy the handle for the Sensor 3 and they did not have the handle. I subsequently went to another PnP and they also did not have the handle. So I went back to the original PnP where my girlfriend bought the razor to see if I could get my money back. As it was open they would not refund me as it was opened already which I agree but then why not stock the handle for them so I can buy it. The manager was not interested to what I had to say. I spend on average R26 000 to R30 000 there a year and will not go back. The razors cost R171.31 your loss.