you can PFD and even Call the collector and see if they will agree to remove the collection upon payment. but if you do it in writing make sure you do not agree that owe and are taking responsibility (this can be tricky).......
after that, dispute with the CRAs as "not mine" and keep track of your dates and let the chips fall where they may.
if the dispute doesnt result in it being deleted, WAIT for the collection to be given to another CA. then dispute AGAIN and it will be deleted with the old CA. THEN make an arrangement with the new CA before it hits your reports.