To make it right before the trip - call
To make it right at the resort - head to the front desk and ask to speak to a manager
To make it right at a park - go to Guest Services
To make it right after your trip - email
Yep. No big secret.
I had a negative experience with a CM at
Disneyland once. We kept talking until we figured out the disconnect and understood each other. He got a kudos put into his file when I went to officially thank him at City Hall.
We had a negative experience with room assignment at AKJ villa room. DH spoke with the front desk then the FD manager and while they couldn't make it better that night, they did the next day. And put a credit on our account.
We had a horrible experience with mold/mildew (I'm so allergic that the moment it comes into contact wiht my nose my nose shuts down and I don't know the difference from experience) in a 2 bedroom at SSR. DH was put in charge and they tried to make it right immediately but I was too out of it to move, then they made it right the next day. Alas part of making it right was a room credit, which required us to set up room charging, which took 2 hours of DH standing at the front desk, so they added to it... And then in the move I left my fave disney fleece and didn't realize it for days... And the day of checkin was during the switchover towards MBs, and had RFID cards, and they kept SAYING that the cards wouldn't work (though they were working) and replacing them...for a 3 night stay we went through 3 sets of cards (with 8 guests), which was irritating.
We had an annoying experience at BWV when the dryer didn't work for our one night "do some laundry before going to Universal" stay, so I got to spend a few hours at the pool watching over laundry on checkout day when we had planned to be at Uni. I wrote DVC member services *to let them know the dryer wasn't working* (we weren't totally sure the maintenance people cared) and they gave me back the points between the 1 bedroom booked for the w/d and the studio we would have booked.
Had an irritating experience at AKL Kidani when the keycards wouldn't work 2 times in a row. Had to trek all the way back. And the CM who said our Jambo experience with room assignment wouldn't happen again but if there was a problem he was on shift the next 5 hours and WOULD BE THERE to talk to...was off shift when we got back 20 minutes later. Then the washer's hot and cold were all wrong (they had thought they knew the fix but it wasn't a fix, so they had to refix it). That got fixed. Then checkout day as the door shut behind us the RFID reader panel on the door fell off. We never told them about that, as we were just OVER the place. Propped it up against the door and figured the housekeeper had to notice it.
So you see...you either take care of it right then and there, or you email later. No secrets no backdoors. Just letting the right people know at the time.
And we have split stays almost every time we've been, so while that seems to be a decent list of issues, compared to the number of checkins we've had and days at resorts since 2010, it's really not that much.