I recently purchased a macbook from apple. After one day I found out the mic did not work, when I received my first facetime call on the laptop. Since I was usi

I recently purchased a macbook from apple. After one day I found out the mic did not work, when I received my first facetime call on the laptop. Since I was using the laptop for some projects I was not able to give it immediately back. I called apple support on chat, the person made me install update and restart mac, consuming 2 hours for no reason. Then I decided to goto the store. At the store they made me wait for 2 hours. Then I was able to present my new macbook without a functional mic. At the store I had the worst experience, the person basically took my laptop for 30 minutes, came back and said I spilled water, they did a test and handed me a 700$ bill to fix it! This was beyond me. I told the person, that I just bought it and it is hard for me to challenge a test that I don't know. It is possible I a drop spilled when I was drinking water/coffee on my laptop. I have a macbook pro, also it works great I have spilled some water on it, usual wear and tear, I don't have a problem with it. However the person was very adamant that I was lying and I better pay the fees or not waster their time. Very confused about my situation, I contacted apple on chat again, and told them about my experience at the store. The chat person called their manager, who again threatened me saying that if I want to challenge their diagnostic test I can, otherwise I should stop contacting them. I have no knowledge about how to find out about this test, what it is, does it consider normal usage conditions of laptops or anything like that. If anyone has had similar experience or knows about this diagnostic test do share, I don't want to pay 700$ extra on a macbook