Quoting Pusherman:" Do you make it a point to repay your debts? Are they top priority for you? I'm not talking about credit ... [snip!] ... her phone number anymore, and I'm kind of freaking out about it because I have always made it a point to pay people back ASAP."
Since being married to DH, we haven't borrowed or owed any money to our family or friends. However, in college occasionally friends would loan me money, or vice versa. I always make a point to pay them back promptly. It's important to me, I dislike being on the losing end of a bad debt (who doesn't? lol).
On the other hand, DH & I have loaned (more like given) money to family/friends. Sometimes we are paid back, other times we aren't. I don't hold it against them though. In a perfect world, everyone would pay us back, however the people we loan money to aren't in the same financial position as we are, so we don't expect much from them.
I think it's awesome of you that you're attempting to pay your friend back. Don't freak out about it too much though. If you don't have her contact information, there's not much you can do. Don't beat yourself up over it.