Locked out of my Orange phone after going abroad?

I went to Spain for a week, but forgot to inform Orange that I was going abroad. As I'm on a contract, I was locked out of my phone - it kept saying my sim card was invalid and that I needed to enter a code. Now I'm home and I thought it would just return to normal. But it's still asking for a pin code (I've never had a pin code on my phone before ever) Is this normal, what can I do?