Iphone 6 randomly typing and clicking on its own?

I dropped my iphone 6 in the toilet last year and i put it in a bag of rice and it worked well afterwards. And this year i dropped my phone on the ground and it shattered the screen but i can still click and type well. Then i had the screen and lcd repaired. But after a few weeks, it started typing and clicking on its own. What is damaged? Is it the lcd? Or the motherboard? Or what?

Get rid of little glitch on Instagram picture?

I've recently purchased a brand new phone (iPhone 6S) I posted a picture on my Instagram account, and a small square glitch appeared on the photo. It was only tiny, but it will not go away. I've deleted and redownloaded the app, I've restarted my phone! It only happens on this device!

How to set up voicemail on iPhone 6?

If I go into the phone app then voicemail it tells me to put in my phone number followed by the hash key, I put my number in, and it says there's no mailbox for that number and tells me to put in my number again?

Payment revision needed on amazon?

So I use the amazon app on my iPhone, and a few hours ago I placed an order using a visa gift card that had $30 and my purchase was $18. Now when I go to the your orders section there's a box that says "there's a problem processing one of your orders" and another box says "payment revision needed" and it's asking me to visit the desktop site and fix the problem. I don't know what to do because I do not own a computer and I'm only able to use my iPhone. Will my purchase still be sent with whatever problem is going on? And if not how can I fix this problem?