Mango Yogurt cheesecake

Here's a picture of my attempt at making Mango Yogurt cheesecake but it was a failure as it tastes more like custard cake... sad =(

I wonder if it's the oven as the oven at Marky's house took forever to bake this cake and still it did not seem very solid after almost 2 hours. (Note that the oven was already set at maximum heat - 250 degree celsius)

I wanna get my own oven but not now as I don't have my own house yet =(