snk-artwork, you shouldn´t design logos for that price ($40) in the first place, that´s not even a decent upfront.
Anyway, i hope you can solve it out with the client, in my opinon if the client accepted your work you should get paied.
I´m not going to judge your work, but logo design is very difficult to master, if you think you master it you should charge much more!
I´m interested in designing the superlogos for those children
Let me know more details through my email!
As far as i know, you can only save SVG´s using illustrator!
Hope this helps