Yes, anytime! A suspension fee of €5 will be charged, and this will deactivate your Moneco card.
If you wish to use your Moneco card again, you will need to reactivate your card. Reactivating the card is free and will reactivate the €1.5 monthly card subscription.
Suspending your subscription also leads to the suspension of the card. It cannot be used until it has been reactivated.