Dear user,
Depending on the court where this incident took place, you can take different measures.
If this incident took place at any lower court, a writ of Certiorari can be filed in the High Court.
If the settlement agreement was part of any evidence, a review petition can also be filed in the High Court, but this has to be filed within 30 days from the day of the judgement of the case during the trial of which, the settlement agreement was overlooked.
I hope I was able to solve your query. Please feel free to leave follow up questions if any.