When someone calls me, i go to answer and it immediately hangs up and says call failure, i also cannot answer phone calls or facetime or even call on snapchat. What is going on?

Hello lilyann211,

Thank you for using Apple Support Communities!

I understand from your post that you are unable to receive calls because when you answer the call it immediately hangs up as do other types of calls like FaceTime. The following articles have steps which may help resolve issues with receiving both regular calls and FaceTime calls which you may find useful:

If you can't make or receive calls on your iPhone - Apple Support

If you can't make a FaceTime call on your iPhone, iPad, or iPod touch - Apple Support

Best Regards.