Am I being used?

So I am currently taking a few classes...in one of my classes I had to present a PowerPoint with a group. After the PowerPoint presentation one lady from the group texted me asking me if I had the pages of the book for our class so that she could do an assignment...so I willingly send her the images(thinking about it now I shouldn't have). Now another group member sent texts at 1am and is calling me so many times at 7am asking me if I have different pages of the book. I didn't bother responding because if this girl can spend money on getting her hair done then she could of bought the book.Her priorities are twisted. I believe that once they heard me say "I help others the best way I know how like how my parents have helped me." I think when they heard me say that it went straight to their heads thinking "Oh she like helping people...I can use her!" What they didn't know is that there is a limit to my help and I'm not a fool ;)