This is a community forum, so while we will try our best to help, we can't see your account.
Go to page 3 of your bill, which shows details as to what the charges are. Sounds like you went way over on your minutes or data, you made some US/international calls, or roamed outside of Canada. Can you tell us what it says there?
Go on Self Serve and look at your bill, then e-bill then your detailed billing. All the charges will be the displayed there so you know what you were charged for. Now if you know that this was by mistake or whatever, contact Koodo via shop, email or calling Customer Care. They will assist you as they have access to your information while we don't.