Do you need it in vector format to print?

I have sent a PDF image of a logo and type to be printed at a print shop. We are getting it printed so that the adhesive is on the front so that the poster can be put in the window and can be seen from the outside. He has emailed me back saying that the text is in vector format, but the logo isn't. He asked me to send him the logo in vector, otherwise he'll do it for $45. I don't understand the reasoning behind needing it in vector format to print!? I've already sized the logo and text, the doent is sized properly to the print size, and the resolution is 300dpi. I don't really know much about vector, but I was under the impression it was just used for making things larger without losing quality (like changing text size).. Why would it/ Or should it prevent him from printing? Thanks is advance.