Is this mold? Should I test it myself?

So the maintenance at my apartment said that it’s not after they tested it. I’m still skeptical since maintenance is known not to do a good job. I’m in az and there’s for sure pink mold in my shower but they said that’s nothing. After moving here my fiancé and I both started to have stomach issues and getting sick. Also the second picture didn’t have that black stuff when we moved in. It developed after. I’ve tried wiping it off but it won’t come off