Cracked the camera glass on my iPhone XS Max. How do I fix?

So I cracked the camera glass on my iPhone XS Max and within a week, so much dirt had gotten In between and you could clearly see it. How can I clean that out? Can I put water in it? I don't think the camera has an opening to the inside of the phone but I'm not sure?

My iPhone 6 is not receiving voicemails?

I got my "new" iPhone 6 back in November (it was previously owned). And I noticed that I wasn't receiving voicemails. People can call me and leave a message but the voicemails don't make it to me. I also noticed if I tried to make a custom voicemail there would be an error so it's stuck ar default. I can see and access my old voicemails from before I swapped phones however. I have no idea how to fix this and I wanted to ask here first before going to Apple for help.

Bottom of iphone 8 screen flickering?

So a while back the bottom of the screen started to flicker, mainly when i had the brightness up all the way, but now it's worse and happens when i hardly have the brightness up at all

the flickering is a copy of whatever is at the top of the screen at the time, so the time, battery, etc. The flickering does not show up when a screenshot is taken

i recently had the screen change and i'm wondering if that could be what's causing it? I'd like any help since it's sorta distracting and bothers me sometimes

Iphone not receiving text notifications?

I have an iphone 8+ that's updated to the ios 12 update. Just starting today i stopped getting notifications from text messages. I've tried everything. Hard reset, do not disturb isn't on, notifications for messages are turned on. Everything is ok and how it should be. I'm getting notifications from my other apps, just not from text messages. It has the red badge come up but no banners, nothing on the lock screen. I have no idea how to fix this.

MY MOM TOOK TURNED OFF MY CELLULAR DATA! Need advice?

Ok so my mom literally takes my phone away for no reason and this time she decided to turn off my cellular data so basically my iPhone is now works like an iPod. (It's been a week now). How should I get it back and have your parents done this to you?

Screen recorder not working?

I've had a screen recording app downloaded on my iphone 8+ for a while but it recently stopped working completely. Everytime i click the button to record, it just doesn't start recording. Anybody know why this is?