Change in roles

So a company came to my college for campus placements for the role of Key Accounts Executive for premium beer outlets. It was also mentioned in offer letter. However after coming here they have moved me to general small outlets with role of Category Development Manager. In the appointment letter it is mentioned role of Category Development Manager which is different from the one in offer letter. What should I do now? I haven't signed the appointment letter yet as it will legally bind me to the company and i have asked them for clarity but got no substantial response and my salary is on hold if i don't sign the appointment letter. Please help me