Sims 3 Custom Sim won't download/install?

SHayes1997

Okay, so a while ago I downloaded a really cool sim from the exchange, but for some reason all my downloads disappeared from my launcher and I had to go and re-download them. Now, it won't install that sim, but it still shows up in the installed items list along with most the custom content included with him (minus the skin tone and hair). It also will not let my uninstall it, because it says that it isn't there. I normally wouldn't worry too much about it, but the sim came with a custom skin that I have used on other sims and now they are completely black. I really want the skin back, but I can't find the sim on the exchange anymore (it was a male sim with the name "Nathan Tran"). Is there anything I can do to fix this, and if not, is there any way to fix the all black sims that resulted in the skin being deleted?

I really appreciate any advice and I'm sorry if none of this makes any since/I kinda ramble a bit.
Thank you!