Is intercession and paying money to obtain a government job considered bribery? What is the ruling on the salary earned by this method, and what is the expiation for this sin?

If you took a right that was not yours by paying a bribe, you have committed a grave sin. You all must repent and return the right to its rightful owners, by leaving the position for the one who was more deserving of it.

However, if you were deserving of the position and were compelled to pay money to attain your right, then there is no blame upon you, and the sin is upon whoever took the money unlawfully.