Hi, I notice that since ypu posted this message, two letters have been registered (55 and 60 days of traveling). They can take a long time to get registered, depending on the destination.
I suggest you wait until they expire (90 days). They can still be registered after this time.
A resend is an option when you think that the letter was lost. You should check if your partner is still active. You can contact your partner before a resent.
If a partner is no longer active, you have the option to mark the letter as "Mailed" once it expire. You can do that in the first page when you log in. In this cases, if you mark your expired letter as mailed and your partner is no longer active to register or to confirm "nor reciving", then your letter will be auto registered.