Same failure with different cards could indicate the camera. Maybe try canned air and also cleaning the cards contacts with a Qtip and very very small amount of alcohol. You might be able to look inside the slot with a very bright light, but it's gong to be difficult. If you used something other than the camera to format the cards, you might try using the camera instead, but if the camera won't read and/or allow you to format, a trip to Canon should be the next step.
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