As of April 27th, 2020, IRCC’s Client Support Centre has reopened to respond to questions by telephone. Due to the continuing effects of the ongoing COVID-19 pandemic, operations are at a reduced capacity. Agents are available Monday through Friday from 9:00 AM to 5:00 PM Eastern Time (6:00 AM to 2:00 PM Pacific Time).
Source: https://www.canada.ca/en/immigration-refugees-citizenship/news/notices/csc-resumes-calls.html