Hello Suvankar,
I assume, as you mentioned, you have already maintained the required Division code in C4C.
You should also make sure that the relevant code list mapping has been done correctly.
Ensure, under ID mapping for integration, you have performed correct ID mapping for Sales Organization, Sales Group & Sales Office.
Another thing is to search the unused/duplicate Division code in your ECC system which might be coming to C4C & throwing errors since these cannot find a matching mapped Division code in C4C.
Try these steps & hope it gets resolved!
BR
Ankur