I agree with some of the people on here, it's kind of fishy to ask for positive feedback without doing trades first. That and you can change bad feedback, I accidently gave someone a bad feedback one time and I could go back and change it. If they wanted to change it i'm sure they would but considering they commented saying you were a scammer I don't thing they accidentally hit the negative experience.
Edit: Also this is against the rules..
"The feedback system is used on The Bell Tree for Animal Crossing online gameplay, Animal Crossing transactions, and forum bell transactions. Feedback should only be given for legitimate reasons. A negative rating should not be made as a response to feedback itself. Illegitimate ratings can be reported to the moderators and abuse of the feedback system may result in suspension."