How can i make absolutely certain negative information on my credit report in violation of the FCRA is deleted from my file?

i referred a customer to a plumber and the plumber sent me to collection. i made it clear the bill should be between the plumber and customer on several occasions. despite my repeated and exhaustive efforts to get the plumber to respond, to bill the customer, to remove the collection from my credit report i have yet to find a remedy. i contacted the customer and they have agreed to help me. when i file a case in district court what steps do i need to make to get the plumber to accept the payment from the customer and remove the information from my credit file?