Wait :-) There are several things that can make a postcard take a long time to be registered. Here are a few:

• slow postal services;
• the user is on holidays;
• the user does not have a home internet connection;
• user didn't understand your handwriting and is trying to figure out the ID by contacting us;

We advise you to try to contact the recipient of your postcard through private message and ask whether that postcard arrived (the ID might be blurred, illegible, etc.).

Please be patient, experienced postcrossers will quickly advise you to do the same - it works!