When I got my phone (a Samsung Galaxy Core Prime running Android 5.1.1) it was sold to me as an 8GB phone. I installed 2 GB of apps and now the phone is full. When I check storage on the phone, it claims to be an 8GB phone, but 4.5 GB are taken up by "miscellaneous files" that cannot be deleted. Even weirder, when I plug the phone into my computer, the computer claims it only holds 3.62 GB. I have already moved every file on the phone that can be transferred to the SD card. Attached is what I see when I plug it into my computer. Was I misled when I bought the phone, or is this a software problem?

Notice that the phone stores only 3.62 GB.
All files that could be moved to the card have
been transferred there.