White MacBook dead or dying. Apple Store store screwing me.

Question

I have had an unfortunate event. Two days ago my white MacBook has started to misbehave. I have turned it on, and it powered itself off after a minute. It probably did that about 4-5 times. Eventually, it booted and stayed on for the rest of the day. This has happened with a fully charged battery and plugged-in. Since it has worked for the rest of the day, I did not think more of it. Weird boots have happened before rarely.
Yesterday, it booted fine, but the keyboard was misbehaving. The option key was stuck in the ON postion without being physically pressed. Some letters worked, others created the option+letter key combination.
So, I have taken it to the Apple Store. I have a got a call an hour later saying that he removed the top case and found a small stain in the bottom-right side of the keyboard, which according to him is evidence of liquid damage. The warranty has been voided. The warranty was actually going to expire today on the 14th.
I find this highly suspicious. I have taken great care of it. Besides a scratch or paint transfer on the bottom case next to the exhaust, which I have no idea how it happened, and yellowing of the touchpad, it looks like new. I have read that the MacBooks turn yellow, mine has in less than a month of use. Maybe, due to heat, it has turned yellow or brown inside.
It's pssible they saw that my warranty was going to expire today and thought to screw me. If it's going to expire in one day, why help him?
They want $230. $130 for the top case. $100 for work. I told him to disassemble it further due to the weird boots. I have not yet received a call back if he has found more damage.
I've seen laptops taking a bath. You could float Noah's ark on them. They have major flooding stains from coke, smoothies, and other beverages. I don't drink that suff, nor have I on the day in question, nor did anyone else use it.
It's my only machine. My only means of communication with the planet is my iPhone. Suggestions?
Thank you.

Answer 1

So, I thought that I should give an update. After the initial quote for $230 ($130 for the top case and $100 for work) to fix it due to liquid damage, I decided to wait a few days before going back to the Apple Store to research the issue. After a few days, I went to the store. The tech who quoted me the price was not there. When I asked when he will be there, I was told that they can't give out his schedule. One of the Genius Bar employees gave me a new price: $750. A new white MacBook is $900 with the education discount.
When I heard that price, I told him to keep it. I decided to call Apple customer support. I spoke to a few people until I have eventually been redirected to someone called Jen. I explained to her that the Apple Store won't give me a straight answer nor have they proven to me that liquid damage has occurred. She wrote some notes down and said that she will email me a case number. She also said that I should take it back, try to have another tech look at it by speaking to a manager, try to take it to another store, or ship it to a depot. That email never came. She lied to me.
I decided against talking to a manager. There was another person there with an iPod. They told him that they haven't found anything wrong with it, but if he wants to buy a new one and trade the old one, he'll get a 10% discount. He was very disappointed and expected that answer.
Clearly, I think that due to the ***** economy, they are pressured to sell to keep the store afloat and deny warranty claims. I decided against speaking to the manager. He would be the one pressuring them.
I took the laptop back. It was dirty and had a few new scratches. I bought a top case from eBay. It's a factory second grade B, AKA scratched to ****, and some of the metal inside was bended, but I straighten it as much as I could. My old one hand an yellow touchpad, but no scratches. I found a YouTube video on how to disassemble and remove the top case. It's 19 screws and it takes about 5-10 minutes. For that work they were going to charge $100. Since they do this all the time, it probably takes them 10 minutes to disassembly, replace, reassemble. They charge more than a lawyer. What a ripoff!
Once I removed the top case, I was in for a shock. There was NO stain. Also, none of the Liquid Submersion Indicators (LSI) were triggered. Those LSIs are sensitive. They turn pink to red from humidity. Actual liquid does not have to touch them. They were all white. One might think that he was nice enough to clean up liquid residue if that was the case. I very much doubt that. The laptop had dust and hairs in it. If the tech had taken the time to clean up a stain, he would have spent 10 seconds with an air can to blow the dust and hairs away. This leads me to believe that he may not have disassembled the MacBook in the first place. He may have assumed that there was liquid damage on the right side since parts of the keyboard stopped working.
After installing the new top case, everything works. There are no issues whatsoever. I'm going to write an email to Steve Jobs because I've been cheated.