Hey there! This is definitely one of the stranger things I've read!
If our Care team doesn't see a record of an outbound call placed to you around the time that you received this call, then I can't imagine what the cause for the call could be. This is definitely something we want a team with account access to double check -- from this public user forum, we don't have a secure platform to verify your account details and take a look. Are you active on social media by any chance? Our T-Force team via Twitter and Facebook do have the ability to open your account up and help get to the bottom of this -- if we need to file a report to our fraud team, that's definitely not a step we want missed!
Just checking in here to see how things are going. Did you get a chance to speak with our T-Force team?