My phone not showing the correct internal storage memory.

[Android Central Question]

It happened not long ago, I use a Samsung A8 (SM-A530F) and i wanted to flash TWRP on it, so i got Odin, downloaded a TWRP rom that was compatible with my phone and i flashed it. I don't know what I did wrong but somehow i deleted my phones OS, so i had to go to Sammobile and flash a new OS into my phone. I succeeded and there were no problems until, i got to setting and i saw that there were two Battery tabs to enter, and i thought that it was no big deal, but today i wanted to install some games and after some installing my phone says that it has not enough memory, and i was like my phone has 32gb of internal storage how could this have happened and i wanted to see it, so i got to storage and my phone only shows 16gb. Somehow it got lost. Please any help?