Keyboard not working, left click behaves like right click
Hey, i have a problem. My macbook air was completely alright when i was using it in the evening. I shut it down, went to bed and then i woke up in the morning, turned on my laptop and all of the sudden, the keyboard didnt work. Also, when i left clicked the trackpad, it behaved like when i do right click(the window with i.e. "copy, save as.." popped up). But EVERYTHING else was/is working like a charm. It feels like the laptop is completely okay, just the keyboard and trackpad are not working. This happend like a month ago. I took it to my local Apple Service Provider, and they diagnosed it as water damage(altough there is no possibility i spilled water on it/somebody spilled water on it). They sent me some pictures. The only part showing some damage is a little place, right where the mag safe connector connects to the laptop. Its maybe an inch by inch big. Aparently, they want me to pay 1000€(1300dollars) so they can fix it. They want to change the whole motherboard, in order to fix this one little piece of it. I would not say a word if the computer was dead or had some other main damage, but i think its ridiculous to pay 1000€(i can buy brand new macbook air for this price) just to pay for the keyboard/trackpad repair. Also, i tried to connect my magic mouse to it and it does the same thing. When i do left click, it actually does right click.
PLEASE help me, or tell me if its really neccessary to remove and change the WHOLE motherboard or if its reasonable to pay that price for this repair.(I live in Czech Republic, where those repair guys would tell me anything to get money. So i dont really believe them, its a water damage because i didnt spill any water on it) And if you have any suggestions what else could be the problem, i would be glad if you shared them with me.
These are the pictures of the broken/damaged piece:
THANK YOU FOR YOUR HELP