Hi Ruby,
Once the 12 weeks linking period has passed, you would only be able to reclaim contributory ESA once you have amassed the required number of NI contributions, the NI credits that you have been getting do not count fully towards this. Your only other option would be to claim Income Related ESA if you are eligible.
This is why we ask people to be very careful before closing their ESA claim! Is there any way you could undertake Permitted Work before making your decision?
Permitted Work