Job always calls me on my days off?

Yeah, I'd ask for a promotion and raise with more scheduled hours 

The company is doing it because they are trying to save money. By calling you in only when they need you, they don't have to pay for all the shifts they would have scheduled.  

It took me a while to stop feeling bad when declining to pick up shifts. The thing is I was hired to work 36 hours a week. Anything over that, I'm doing them a favor. Same for you. When you go in on your off days, are you ending up working full time hours? They'll keep using you that way because they get a full time employee without paying for benefits. Don't let them use you. It's okay to say no and you don't even owe them an explanation as to why you won't come in. When my boss asks why I can't come in only day off I literally say "because it's my day off." It's the truth and they can't punish you for it.

yeah that's retail life, especially part time. just say no, that you can't make it. you do not have to give an explanation as to why and they can't ask you. if you're not scheduled, you're not obligated. 

Take the hours offered when you want, politely turn them down when you don't. Youre basically complaining about getting opportunities to make more money. Just think about that. There may come a time when you need those hours, but they aren't offered any lomger.

I agree with Nikki. Say yes when you can and politely refuse when you can't. It's retail. The hours suck. Co workers suck and call out. And definitely talk to the manager about review and your future opportunities but don't complain about them calling you. You sound the most reliable so they will always call you first. But they have no right to demote you for turning down shifts when you are scheduled off. Just be positive and don't let their scheduling problems be yours. 

In retail there is never an "enough" Just take the hours! LOL

Set up a meeting and ask for a performance review to discuss a possible raise and/or increase/change in schedule so that you are able to plan your time appropriately when you are not scheduled in. 

I have a very simular problem as a part time shift-manager within the fast food industry. I usually work 3 days a week and I get texts/calls on almost every single off-day where people try to call me into work. I am often asked to come in for people who are not managers along with other managers. (I am not suppose to work their shifts unless it is a REAL emergency because I get paid more, therefore, it cost more to keep me there). I often do come in for people but it gets to the point where I would literally be working full-time if I said yes every time- So of course I have to exaggerate and come up with excuses occasionally- which is OKAY. My coworkers like to take advantage of me because I’m a nice person who struggles to say no. I know they lie about being sick sometimes because we have caught people via Snapchat. In addition, people tend to call in more on sunny days and weekends and they call in less around holidays 🤔 (when they need money for gifts so they suddenly grow a pair and work there shifts no matter what like I would NOTE: IVE NEVER CALLED IN AND IVE WORKED THERE FOR 2 YEARS)Anyway, you seem like a very nice hard-working employee. The people you work with seem to have been taking advantage of you. Companies love to do this with part-time employees yet even though you are so hard-working it can be really hard for part-time employees to get raises.Lastly, I know this response is like 2 years late lol but my point is that nobody should feel guilty about not coming in for people when you have legitimate plans. To me, focusing on colllege- perusing higher education is way more important to me then my dead-end job. My family is also very important to me. Feel free to argue that I’m being “selfish” or something or that coming in for people leads to raises (it most often doesn’t😐) Also, you can claim that she should take the extra hours because it’s more $$$; I’m not sure what her full situation is but let’s say she’s a college student for example, focusing on ONE’S FUTURE IS MORE IMPORTANT than having extra money to spend even if that means not having money to pay for things other than bills.

Some times you just have to push the issue. My past job was like that. I told my manager and the GM they had to either start scheduling me the hours or expecting me to become very busy on my days off. I was also constantly given manager duties as a crew member so I told them I had to be made manager within a month or I'd seek other employment. I was a manager with a 40 hour a week schedule within two weeks. The raise was nothing special, but it was still worth it to know my schedule in advance. The job actually didn't last too long after that, but that was due to some other ridiculous issues.