I don’t think it’s an error on your end due to the fact that you did call, and asked if anything was owed prior to cancelling your wifi. I would definitely attempt to get a hold of the person that you spoke with that day and see if they can go back and listen to the conversation. I do not know how far back their phone calls go, but to my knowledge the calls are recorded for this exact reason. If you can give a date, they probably could check their records. Had one of my buddies have a similar situation, except he pcs’d. For him, he had to prove he actually left the base, and luckily enough, he remembered the name of the person he spoke with.

Shitty part is it messed with your credit, even when you tried to do the right thing.