They identified themselves as HSBC's security department, asking about a suspicious charge. The circumstances do look strange, if it is what they are saying it is.

I think it is a scam. Trying to collect HSBC credit card information.

This is a legitimate HSBC fraud prevention call.  If you are concerned about the 416 number the call is coming from then phone them back at the number on the back of your HSBC Mastercard instead and you will discover that they are simply verifying recent transactions that don't fit within your normal spending pattern.  You want calls like this!

Idont have a master card account....

B***s***. They asked me for the 3 digit number on the back of my card.  Legitimate banks would never do that!