Seriously? People 'show off' because of the number of contacts they have? That's the most ridiculous thing I've heard this week.
The point is that you said that the numbers are important. If they're important then surely you should save them. Nobody gives a flying hoot about how many contacts you have. If a number is important then save it. Simple.
Anyway, lesson learned and hopefully you will take steps to ensure it doesn't happen again. Whether than means saving important numbers (either as contacts, notes or even writing them down on a piece of paper), changing your entire platform or any other method, I wish you success.
/edit - were these important numbers ones that you've called? If so, check your bill, assuming that your carrier provides a fully itemised one.