An Apple authorised reseller opened up my iPhone 7 Plus and found handwriting on the inside
Need some input on this weird situation.
I’ve been having problems with Siri. When I want to talk to Siri, sometimes the bar at the bottom is all wavy and colorful as if it’s hearing a lot of noise even if there is total silence. The issue comes whenever the iPhone is exposed to steam or a bit of moisture. E.g. if I wash my hands and a bit of steam rises and the phone is on the window sill above the sink, semi-exposed to a bit of steam. Siri can’t hear anything I say unless I leave the phone on a bench for a few days and slowly it comes back and eventually starts working again. Sometimes it comes out of nowhere, like I left my phone in my car while at work and came back at the end of the day and the issue was there with no moisture, so I’m not 100% sure of the cause. I updated the software, reset everything, turned Siri on and off, and the problem persisted.
I took it to an official Apple store hoping to get it repaired or replaced and they just cleaned it. The issue persisted even after I treated it like gold, avoiding any exposure to moisture, and they just cleaned it again. The issue came back again so I took it to a different store, this time an official reseller, and they opened it up and found handwriting on the inside and a missing screw and they said it looks like a 3rd party has opened it up. Honest to god, I have NEVER opened up my iPhone and I NEVER took it to any 3rd party. No one other than the official Apple store and the reseller have ever opened it up. But they’re telling me the warranty is probably void because of that. What should I do? I don’t know what to do if the issue comes back again.
edit: additional info: I bought my iPhone 7 Plus brand new from an Apple store, also it has never been underwater or dropped
edit2: I don’t know why my replies aren’t showing up. Mods pls