What wrong with both my sister!

Seriously don't know what wrong with both my sister.. one keep spending money on herself and didn't gave my mum money every month... my mum always like to come to me and borrow money from me instead of her.. my one month paid sometime is really just enough only.. i still have to save some emergency cash.. i don't think my useless sister will save at all.. that only my older sister now come my younger sister. asked her to bring our pet rabbit to have it nails cut by pet shop, she booked the appointment which is tomorrow so i pass her the cash. after my mum come back from work, my mum told me that my sis told her to tell me that she can't bring the pet rabbit down as her school end late.. it's like.. WTF la can't she like tell me instead of telling my mum then tell me.. say what scare to tell me.. what the heck la... is there something wrong with sister telling her brother things.. is it so hard??? that why i say i don't really like my family.. that the reason..