Are you serious? You want the contest holder to put on the logo "Design made by..."? Ridiculous. Besides, it's not Freepik rules but Freelancer rules, that said you CAN'T use clippart. When you submitted the design in this contest you clicked and accepted that it was your design 100%, right? But this IS NOT your design. So you are violating the contest and site rules!
It is. What part of "This design belongs 100% to me..." when submitting the entry you don't understand? Besides, read the rules and you'll find clippart is not allwed neither. Must be your work, not others. You lied and cheated!
This is cheating! Not allowed on this site. I will report the entry. Copied from here: https://image.freepik.com/free-vector/realistic-coffee-logo_23-2147503980.jpg
Yes, they are totally for free. We only require you to attribute the image or vector to its author every time you use our resources.
Our contents may be used freely inserting the attribution:
In personal and commercial projects.
In websites, presentations, printable elements and so on.
Totally or partially, using the full design or modifying it as well as integrated in your own designs.(ref : http://www.freepik.com/how-to-use-the-website)