robary in Shell garage

I am having a very best day. bought my new car,i went to shell garage to pure petrol. payed cash and the person who was assisting me put a pipe but did pure petrol. i noticed on my way leaving that the guy didnt pore petrol. when i went back he told that he did which was a lie. I will never ever use any of the shell garage. their consultant dont value the customers. instead of them to service us they are robing us.