When your Raspberry Pi 2 is does not hold the integrated sd-card anymore, than your one of many people who face the same problem.
I have found an easy way to repair the sd card holder without fire and iron and explosions:
You can use an elastci strap and you will only loose 2 of your 4 USB-slots with this method.
A small and strong elastic strap can hold the sd cartd in the sd card slot and fixes the problem easily and smooth.
Your Raspberry Pi works again without any problems.
If you want to repair your sd-card slot like a pro, you should watch this youtube video:
Buy a new Raspberry 3 model: