Employment provider forced appt on me

Hey guys, so I've been on DSP since october and I had my phone appt to figure out what my obligations are. Im working about 8 hours a week and i also volunteer. The lady said i was meeting my obligations by doing that and didnt need to do anything else, sje even said i dodnt need an employment provider. Fast forward a month, I get a call from a employment provider trying to book me in, I told her I dont need them amd im already meeting my obligations amd she said she would check it out and give me a call back if I needed to come in. Fast forward another month I get a letter from the same place telling me I have an appt booked. I dont know what to do? Does this mean centrelink was wrong. Is there a way to prove what was said in my obligations phonecall. This letter didnt even have my full name on it. Just my first name. I dont want to see them or have anything to do with them but they just wont leave me alone.