Well if your PS2 is un-modded (I'll assume it IS modded bcz u corrupted data ) just start the PS2 with no game in it and go through the menu until you find the memory card, then delete w/e u don't want.
Take it back to the store u brought it from if you still have the recepit and get a new one, If that dosnt work and your ps2 is still under warrenty report it in for repairs.