Why does this always happen? I ask my mom and sister days in advance if they can take me to the…

Why does this always happen? I ask my mom and sister days in advance if they can take me to the store because my boyfriend's truck tires are showing cords on the front and I don't want to have our daughter in it unless we absolutely have to, they said that my sister is off today and they would be able to take me to the store this morning... Then I message them this morning and get told oh my sister has to work today and they don't want to go to town until about 4 when my sister gets off work. Like I understand if she gets called in but I feel like they should have told me before this morning when I ask when they are heading here. Just want to get some groceries