What is the position of religion and Islamic law on working as a lawyer and dealing with banks in a country not governed by Islamic Sharia, given the commitment to agreements that include usurious interest which cannot be easily avoided?

It is not permissible for you to be an agent for usurious banks in filing lawsuits or collecting funds, due to the collaboration in sin and aggression involved, in accordance with the Almighty's saying: "And do not cooperate in sin and aggression" and His saying: "And do not be an advocate for the deceitful." This ruling applies whether the banks are in an Islamic or a disbelieving country, because disbelievers are addressed by the branches of Sharia (definition).