Is it coincident? Oil change and alternator brakes
 

I had oil change from Toyota center last Wednesday. The following day, I noticed the plastic shield underneath dropped out on one side. Two days later, I heard a weird noise in my car without any warning light on the meter panel. So, I thought it was the belt noise. Last night, my car completed died and get towed back to Toyota. Now, I was told the alternator was broken and there was a missing part that help to keep the plastic shield up. Is there anything relate between these thing with oil change service?

Mine is Toyota Camry XLE V6 2005. It is my partner.