1) When Harry was a little he used to cry a lot. Oh, no, he didn't. He used not to cry a lot when he was little.
2) They used to explore the forests when they were in South Africa. Oh, no, they didn't. They used not to explore the forests when they were in South Africa.
3) She used not to like fish. Oh, yes, she did. She used to like fish.
4) He used not to work in that company. Oh, yes, he did. He used to work in that company.
5) We used to be good friends. Oh, no, we didn't. We used not to be good friends.
6) Nelly used to be interested in stamps. Oh, no, she didn't. She used not to be interested in stamps.
7) John used not to be fond of animals. Oh, yes, he did. He used to be fond of animals.