I'm so mad, I applied to a supermarket and called many times but no one will call me back?

I applied to a Stop & Shop supermarket and I’ve called about 4 times in the past two weeks and they wrote my name and phone number down and they’d call me to set up an interview. I even went in there once and asked them if anyone has looked at my application and I saw them write down my name and number so it’s not like they’re lying. My mom says that I’m just not trying hard enough, but I don’t want to call every single friggin hour. What should I do?!
I need a computer for school very badly, and my parents won’t pay for it so I really need a job. Also for when I take Driver’s Ed. soon, I need money for that too. And car insurance once I get my license. So you see, I really need a job.
When you first applied to a job, did you have to call back many times before you actually got an interview?! How long did you have to wait? Any feedback is appreciated, thank you
Oh and I know they’re hiring, they always are, and I know they would tell me that they’re hiring or not.
And sorry that this question is so long, haha.
Not many other places are hiring, or will hire a 15 year old.
although I will be 16 soon, but I need a job right now :[