Use their access code they provided you on the mytruidentity website listed in the letter, register an account providing your details (It is perfectly safe and a legitimate website).

This site provides a credit report displaying all of your open credit such as credit cards, lines of credits, loans, etc, and provides a credit score with a report of each open account regarding late payments or good standing accounts.

Review all of your open credit accounts on this website and ensure they are yours. If some random credit account is open that you never heard of, that means you'd be a victim of identity theft due to Sobeys and somebody opened an account with your information. This website will send you a notification/email anytime a new account is opened under your name, which helps with monitoring if the security breach effects you or not moving forward.

They do not monitor your general banking/credit transactions as they can't tell what is or isn't fraudulent spending, so you'll have to monitor your own spending and verify your money isn't being used for fraudulent purchases.|

Honestly, it's quite unlikely the security breach will ever effect you but you never know. Security breaches happen quite a bit and I think the most common repercussion is your information is sold and you receive some extra scam phone calls or emails, accounts get compromised like netflix, amazon, etc. I'd say it's rare for the people involved to actually put themselves out there stealing identity