can someone please help?

so I can't remember if this is a TV show or a manga but there was this girl who worked at a supermarket/convenience store and one day, this guy she used to have a crush on in high-school started coming there. They started talking and he decided to "borrow" some money because he was training to become an idol. After that, as soon as he got famous, he ghosted her because she was only his "moneybag" or something like that....

Oh and I think she exposed him on some online forum