First call CRA and tell them what happened, then
you can do your 2018 return Online here: https://ww1.2018.turbotaxonline.intuit.ca/
Or you can use TurboTax CD/Download for 2018: https://turbotax.intuit.ca/personal-tax-software/download-tax-software.jsp
If you are in Canada or the United States, you can
call the CRA at 1-800-959-8281. If you are somewhere else you can call
613-940-8495. Here are more ways to contact the CRA:
https://www.canada.ca/en/revenue-agency/corporate/contact-information/telephone-numbers.html
