Thanks Christine, Matthew
I’ll keep your suggestions in mind 
And I did refrigerate my pie for an hour before baking, but it still didn’t stop the crust from flopping down. I guess it’s like what Matthew had pointed out… the flan dish provided zero support to the pie edge.
I haven’t used maple sugar before. Is it sweeter than normal white sugar? I just wanted to camouflage the tartness of the apples with a little more sweetness of flavor. The apples I used were a bit too tart for my taste. I could only eat my pie with a serving of whipped cream which sort of neutralized the flavor, but I would have liked to eat the pie on its own.
I shall look out for different varieties of organic apples
and give it a shot again. Thanks for all your help.