what should i do next?

[Kittysue]

You don't love her - you hardly know her. You have a crush on her - that's different. You can't love someone until you truly know them. Being her customer is not knowing her as you don't know what she is like away from work, how she acts around her friends, how she talks to her famly, etc
And she's not interested in you. If she won't give you her number, she's not interested. You look like a stalker if you keep trying to get her number. If she liked you as anything more than a friendly customer she would have given you her number.
Don't waste your time pursuing a girl who is not interested in you. It's not worth it