My title is supply and logistic agent yet I do a heckful of purchasing and finding new suppliers and buying the correct quantities to make sure production doesn't stop. All these tasks are something a purchasing agent would do and a purchasing agent is paid a couple bucks an hour more than a supply agent. I told HR that purchasing isn't what I should do but she told me that's what a supply agent does. Multiple job offers are saying the contrary and backing me up. I don't mind the purchasing and all but I wanna be paid properly. Note that I was “lucky” to end up where I am because I have no experience. What should I do ?