Why can't I extract the entire .rar package completely?

[AC Question]

I think there's something wrong with my phone. I've noticed this after trying to extract 3 different set of .rar files, I always end up with a message like, "extract error, file missing" or I am able to extract the package but I am not able to extract the package completely. For example I am about to extract a 300mb .rar package, after extracting, the folder's file only contains 200mb.