So you've established na dili kinawat ang item .... so this is issue is not between you and the girl but between the girl and her ex-boyfriend. They should come up with the money and buy the item back from you. Have the girl talk to the her ex .. sila maoy magsabot ug unsaon pag lukat sa item ..
OR ... you confront your neighbor .. tell him the whole situation .. ask him to talk to his EX-Girlfriend and settle everything OR have him reimburse you for the item ..
Another issue ana is that walay resibo... walay bill of sale... hopefully you have something to show nga imong gipalit ang item with the exact amount.