Erol, what are these hatch doors made of? Around here, the typical hatch door is a square of drywall or a thin square of luan paneling.

I know you're frustrated but you can't put the bill for repairs of damages incurred by you on your client. You just need to be more careful. Try propping your ladder against the wall and freeing up the access panel by hand instead of with the end of your ladder. If it doesn't want to move with hand pressure, things are not likely to go any better by forcing the hatch open with your ladder (as you already know from first-hand experience).