Itunes Deleted My Music

I updated ITunes to the latest version and I seem to have deleted my music. I asked my friend who also have the same issue but she said she found her music in one of her school folder after she searched for it.
I have gone through my computer, by folder and through the search program as the "ITunes Resolution" site said. Still i have yet to find my music or get any help with this issue.
I searched for .m4p, .m4v, .m4b, .mp4, .m4r, .m4a, .ipa, ipg, .ite, .itlp, or .epub to my search bar, and i continually got no results. That is the only thing the ITunes Support said to do. But this didn't work for me and I paid a lot of money for all my music and I think it's pretty ridiculous that I can't get any help on getting it back.
I called the help line and a computer told me that because I didn't have a Mac it couldn't help me and to look it up on the site. I am still a consumer of Apple good, I don’t see why I get less service because I choose a different OS.
I want to know any other suggestions about what i can do or even better who i can talk to help me my music back or at least get some kind of retribution for all the music I lost.

Respectfully,
KS