If you successfully sent your tax return via NETFILE, then you can check the status of your return using the CRA's My Account, or you can call them and ask.
If you are in Canada or the United States, you can call the CRA at 1-800-959-8281. If you are elsewhere, you can call 613-940-8495. This page has more ways to contact the CRA: Contact the Canada Revenue Agency
The Canada Revenue Agency's goal is to send your refund within 2 weeks, when you file online, but it may take longer if your return is selected for a more detailed review.