Walmart cutting hours

I’m a part time for 3 years now and I’ve had gotten a fixed schedule of 32 hours every week, and now more hours are being cut off almost every week, from 16 hours to 24 hours. I ask my coach and he said the store manager is doing that, is it legal? Or is there anything I can do. Hence ever since that store manager came, he’s been cutting almost the whole store hours, even if you full time