Note that your Rejsekort can be blocked before the applicable expiration date. You can see if your Rejsekort is blocked in the self service. If you have a Rejsekort Anonymous you can see if your card is blocked at a Rejsekort Vendor, by using a Rejsekort Vending Machine or by contacting Rejsekort Customer Service at +45 7011 3333.
Be aware that the function is in Danish. To find the expiration date use the buttom "Tjek udløbsdato".