You have to compare what you are getting now with the offer in Congo.
Does the offer include medical insurance cover, is it tax free tax paid or before tax. What is the standard of accommodation, is it shared, is the food suitable for you. Will you have other Indians working with you.
Compare the Indian income against the Congo offer.
As you will be there for 2 years will you have time off locally in those 2 years. What is the condition of the facilities that you will be working in. What are work hours.
Will your money be paid into a local bank. How easy is it to transfer money form Congo to India.
What I am saying is look objectively at and compare the offer with what you are getting now.
The grass is not always greener on the other side of the hill.