Seriously my kids safety needs further details when I ask for help?! The seat belt kept tightening so I couldn't get his…

Seriously my kids safety needs further details when I ask for help?! The seat belt kept tightening so I couldn't get his car seat out to position it better and the whole time I asked for help my sister said "help? With what?" I finally yelled the seat belt keeps fucking tightening and she refused to help me cause I yelled at her. Are you serious?!