Ok, first off breath. Deeply. These things just happen once in a while. Really it is ok. Strangely enough the Canadian Revenue Agency (CRA) isn’t going to eat the fresh from your bones when you make a typing error or copy the wrong number down. They may not be all that happy, but they won’t eat you.
To deal with the situation you fill out one of these and then send it off the CRA if you have received your notice of assessment back. If you haven’t got your assessment back I would suggest just waiting, they might just find your error themselves and adjust it for you.
Yet before you start all this paperwork keep in mind the last item on your T1 tax form. The CRA doesn’t issue refund or collects money on balances less than $2. It simply isn’t worth their time to fix errors that small. So if it is a truly minor error, forget about it.
On the other hand if you feel the CRA has made a mistake you might want to consider reading this and talking to them. If that doesn’t help you might want to consider bringing in a tax professional to deal with the mess.
Overall you need to remember that you have to document everything when dealing with the CRA and when you do talk to people get their full name and phone number so you can talk to them again if you need to. The idea is to cover your ass and make sure you can prove everything in court if need be.
Of course keep in mind I’m not a tax professional. The above is only my own opinion and should not be considered advice.