Telus is apologizing to customers after persistent problems with its email system that began last week.

"Telus technicians continue to work diligently to restore email access to all users and brought additional servers online overnight," the company said in a statement on Sunday. "Telus is incredibly sorry for the disruption and the significant inconvenience our customers have suffered as a result."

The company said the problem began in the early morning hours on Thursday. At that time, a vendor was repairing failed equipment. Telus said "a flawed repair procedure" took the entire email system offline.

Most customers had access to their inboxes restored on Friday, but the system "experienced some performance issues as customers re-engaged with the platform," Telus said.

Saturday night, after numerous complaints from customers who still hadn't had their email service restored, the company shared a video on its social media platforms from its chief customer officer Tony Geheran.

"We've let you down, and we are sorry," Geheran began, adding that he wanted to personally apologize for the situation.

Telus said it brought additional servers online overnight Saturday and planned to enable webmail on them Sunday. This, the company said, would allow all customers to send and receive new messages through a web browser. Mobile apps would not have access to the system immediately.

"As data is recovered, old messages will be restored to the mailbox and full access will be available," the company said.

"We are providing webmail access at this time because there is a risk that emails and contacts could be lost if we enable our affected customers to use mail apps, like those on their smartphones." Telus said. "We are doing everything we can to protect our customers and their data until we have a permanent fix, which is why this new function will be limited to sending and receiving new emails, and enable email forwarding to another account or platform."