I recently created a build that has a fair amount of CC.. Both sims3pack and package CC. Now all other builds i've made has uploaded fine but for some reason this one doesn't. Alot of the CC is missing when others download it.

I then decided to extract everything, merge and turn it into a package file but then people can't find the building.

Where am I going wrong?

Are you merging all the extracted package files together and placing them in the Mods/Packages folder? If so, I believe that's where you're going wrong. The largest extracted package file is the actual Lot (or building) and should be placed in the Library folder. The rest of the extracted package files can then be merged if you wish and placed in the Mods/Packages folder.

Maybe this will help explain it better.
Tutorial: How to Install Lots (sims3pack) without using the Launcher

Hope this helps! Good luck!

Thank you, I already had a tester put it into Library folder and all of the custom content was missing.

I'm not quite sure what you mean by 'tester' but did you put the custom content package files in the Packages folder and the Lot/Building package file in the Library folder? If you did and it's still not working then I'm not sure what else to suggest, sorry. :-)