What should I do; My Macbook Pro Retina 13" performing worse after a visit to the Genius Bar.

Question

To give a little background; my MacBook is my baby. I keep it as safe and clean as I possibly can. The only damage that has come to it is a tiny dent in the left corner of the screen, when my little sister took it, ran, and dropped it on a wooden floor. It's my pride and joy, and I would never mistreat my computer. I don't loan it to friends, I always know where it is, and I do my best to keep it from dying. The only thing I do which is problematic is not shutting it down often enough; I usually keep it on for days at a time, I don't sleep much and spend a lot of time on my computer, but for such a high price, I was expecting that it could handle it. Onto the problem.
My computer was having minor problems with the trackpad and keyboard and had been since I'd bought it, but I hadn't been noticing it much until recently. I remember my mom pointed it out when I first got it and I told her she was crazy. I suspected a little hardware problem that my AppleCare would cover. When I went in to the Genius Bar, they opened up my computer and told me I had serious water damage. I was shocked as I'd never brought my computer close to water; I don't bring it in the bathroom, so no condensation, I have never spilled on it, I don't usually eat or drink around it, etc. I was given very minimal detail or explanation, simply told over and over that it was water damage, and they told me my AppleCare had been deactivated, which made me even MORE upset. The store told me it would cost almost $1000 to fix, at which point I was about to cry since that's almost the cost of my computer. I was going to wait until I got home to get an opinion from my hometown Apple Store, as they've known me for a long time and I was upset with the unhelpful service at the Genius Bar around my college.
My current problem is that I don't think I can wait until May. My computer has been acting up ever since the Genius Bar visit earlier this month, my screen is shaking and the color is going in and out, sound is acting strangely, and I'm really, really upset since none of these problems existed before my visit. I didn't feel it was a problem until recently, since it was pretty scattered and I felt like if I ignored it until I got home in mid-May, I could get it fixed then. Now, I feel as though something was jostled or screwed with while they were checking my computer and it's causing me a lot of problems, problems that are interfering with my use of this otherwise awesome device. I really love my MacBook, it's the best computer I've had, but I am at my wits end.
AppleCare is insurance, and I don't understand how they could take it away for something that I have no control over. When I bought AppleCare, I was told it would cover any damage that happened to the hardware or software of my computer, which is the whole reason I bought it! I wouldn't have wasted money on it if I knew this was a way to take the responsibility of fixing my computer away from Apple! I am beyond angry with the service I received, the "rules" of AppleCare, and the performance of my computer after the visit. I can barely type this since my screen refuses to stay still or one color! I was having absolutely no screen problems before this visit!!!
This is my last resort; I may return to the Genius Bar sometime next week for a reassessment. I am extremely upset with the service I have received and the new problems arising. This computer is barely seven/eight months old. It should NOT be having these problems. I can't help but think it was a manufacturing error and I was given an incorrect diagnosis. As a final, desperate cry for help, I thought I'd turn to the support forum for advice; is there anything you guys think I should be doing or any way I can possibly fix this problem myself/without Apple since apparently I have no insurance even though I paid $250 for problems like this to be covered?

Answer 1

Welcome to Apple Support Communities
Hold the Power button until your Mac turns off, and turn it on again. As you tried to install a firmware update, plug the MacBook to its charger before turning it on.
Note that firmware updates are installed in the next startup, so don't worry about this, as the update hasn't been installed yet.
Respecting to other freezes, it may indicate a hardware problem. Check if the same freezes happen in the future