I wrote to the hosting company in wich servers the hackers were where based (I discovered so many things on their hidden places, you wouldn't beleive!!!) And guess what? - I never received even an appology from that company!
So, I had to start my website entirely from the beginning.
Now I use several ways to protect the code and MD5 Comparison Toolis one of them. It is easy to use and it gives you a priceless helping hand when you want to look a bit deeper.