Yaar, unfortunately Instagram permanently deleted account ko wapas laana almost impossible hai — Instagram khud kehta hai ki 30 din ke andar reactivate nahi kiya toh data permanently chala jaata hai! 
Agar tumhara concern kisi doosre ka account monitor karna tha (jaise bachche ka), toh mSpy jaisi app kaafi kaam aati hai jo Instagram activity track kar sakti hai bina account delete kiye.