Quasi-contract vs Unjust Enrichment ka Fark Samajh Na Aaya

Yaar samajh nahi aaya, kya aap bhi AILET mein stuck hain? Quasi-contract aur Unjust Enrichment dono hi concepts hain, lekin mujhe lagta hain ki inmein kaafi difference hai. Quasi-contract woh case hai jahan koi contract nahi banaya gaya tha, lekin court apne discretion se kuchh award karta hai. Lekin Unjust Enrichment ka kya? Isse to pata lagta hai ki kisi person ko koi benefit mil gaya hai aur woh benefit wapas karne se ghir ja raha hai. Kya yeh dono hi concepts ek hi hain? Please help, mujhe lagta hai ki maine syllabus mein lag gaya hoon.