Delta represents AF and KL in the North American market, and therefore that is presumably why the local customer complaints department answered your query.
I think you are undermining the credibility of your complaint by using statements like "The plane was hardly able to get off the ground" and "the plane seemed unable to climb".
You can find numerous reports of dirty planes, poor food and so-so service on any airline. If you think the A330 is an old plane (the average age of AF's A330 fleet is only 15 years), you should try BA's creaking fleet of 747s (average age: 21 years - and being refurbished to fly for another 7 years) and KLM's 747s (average age: 22 years).
And you mistakenly assume or imply that the A330 is the only aircraft AF flies to Canada.
Today's AF344 to YUL is a B777-300ER and
yesterday's AF374 to YVR was on a B777-200