Internet of Things (IoT) comprises of a huge number of connected devices that can communicate within the same network and across the networks. IoT enabled Wireless Sensor Networks (WSN) are getting growing interest due to its wide applicability in healthcare, patient monitoring, transportation, and surveillance. The main issue is that the network is mostly deployed in hostile environments where an attacker may physically destroy the CHs or other technical fault may occur. It isolates the cluster and causes loss of sensitive data from that region. This paper presents a Critical Data Reclamation (CDR) protocol that provides secure data transmission for isolated clusters. We present the data transfer, data aggregation algorithms for sensing nodes and data receiving and extraction at CH and sink. We performed extensive simulations using NS-2.35. Results prove the dominance of CDR in contrast to counterparts in terms of communication cost, energy consumption, and resilience.