Is the money obtained by taxi offices considered unlawful (haram), given that they no longer provide any services in exchange for this mandatory payment for renewing a vehicle's license?

There is no harm for the license applicant in paying the fees that the government department requires him to pay to specific offices. However, whether the office owners are entitled to these fees depends on understanding the reason why the government department mandates this. The general principle is that government bodies do not impose such matters except for a public interest. It is advisable to ask the people of knowledge in the questioner's country who are familiar with the regulations and laws.