If you lost your student ID just go to the registrar in gilmour hall and they will replace it for you at a cost of $30. Hopefully you find everything you lost
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What if my ID card is lost or stolen?
If your card is lost or stolen report it immediately by phone or in person to the Office of the Registrar or the MAC Express Centre to have the card invalidated. To have a replacement ID card issued you must personally visit either the Office of the Registrar or the MAC Express Centre. A $30.00 fee is charged for replacement of the ID card."
http://registrar.mcmaster.ca /regis...d-cards.html#5
For presto:
"If your card is registered, immediately report the loss:
Report a lost card online.
By phone at 1-8-PRESTO-123 (1-877-378-6123).
In person at a Customer Service Outlet."
https://www.prestocard.ca/en/StaticContent/FaqLost/