First of all, send them a letter asking for the necessary changes you want. You must be seeking a change in the credit bureaus’ database or a change in the collection agency’s policy of collecting debt.
If there is no response from their side, let them know that you are filing a court case against them. Send them a settlement letter mentioning the changes you want and the amount of money you demand in the lawsuit.
It’s very likely that they will accept your proposal and try to solve the dispute personally instead of going to the court. It will save them from losing their time and their reputation. In this way they could also save the court fees and other charges, although they have to pay you.