We do not see any problem with cancelling debit cards that have never been activated by customers with a thirty day notice. Under Regulation E, the cancellation of an access device does not necessitate a change in terms notice. 12 CFR 1005.8(a)Comment 2(ii), Official Staff Commentary, Section 8(a). If your card agreement has no other requirements, we do not see any problem with deactivating the cards after giving a thirty day notice.