Request support for pausibg my laptop

From 3 days ago my laptop paused by xfinity, I did everything, turn on off modem , plug in out , install uninstall the app, finally i went to an xfinity shop that i bought my service and they gave me a new modem , but nothing works.. i am an online student and i will have a midterm tomorrow , i need to have internet on my laptop . Please help me as soon as possible. Otherwisr i have to cancel my contract.