Snapchat banned you. They also ban access from the device you were using. Unless they lift your ban, you will never be able to use Snapchat with that phone again. Not only that, if you sell your iPhone, no one else will ever be able to use it on Snapchat. Not even under a different account.
If you try to access your account from a different device (iPad, Mac, different iPhone, Windows PC), they'll ban those, too, once they see you're accessing the banned account from a different device. Then that/those devices will never be able to connect to Snapchat again, either.