What happened is this. Your hard drive failed. Someone you know said "it was hacked" and you believed them. When you took it to Apple, and said to them that someone you knew (who has less than half a clue) thinks it might have been hacked, they opted to nod and smile at you rather than have to explain that your hard drive failed and have you yell at them for useless quality control.
You experienced filesystem corruption, but that doesn't necessarily mean it was the hard drive. It could be bad memory, bad motherboard, or even a bad power supply.
My first CoreDuo MBP corrupted its own filesystem due to a faulty motherboard (it also had intermittent lockups and wake-from-sleep issues).