Macbook Pro doesn't start up or charge - not working

I'm so frustrated. I woke up one day and my macbook 13" 2011 wasn't turning on or charging anymore. So I had it checked it by the only guy in town who knew how to open it and he saw corrosion. Probably, I spilled water and didn't notice, so I continued using my mac until a day I couldn't. He cleaned it and it worked on time, but it was just to turn it off and it didn't start up anymore. I was in Orlando for the past days and I took it to Macdoctor, but I didn't say anyrhing about corrosion because I wanted a truly diagnosys. They replaced the magsafe door and the hard driver and it was just fine until today, when it isn't turning on anymore. And neither the charger appears to work, no lights appear, like before.

Maybe is there corrosion somewhere?

What do I have to try?

Should I try to sell its parts on ebay and save to buy a new one?

I am about 6 months on this problem.