DON'T BUY GAS FROM BP LAMBTON!!!

I bought an LPG 9KG Gas on Friday the 1st of November at BP Lambton, I used the Gas on Saturday only for it to be used up within an hour of opening it. I returned it on Sunday the 3rd, I was then told to leave the empty and fetch it on Monday only to be told that my case was not dealt with be the person in-charge of the that section. when i when I went back on Tuesday they told me they can not exchange. DO NOT BUY GAS FROM BP LAMBTON!!!