Have they actually tried to take anyone through courts for claims? They wouldnt have a leg to stand on as I have proof of postage, an email stating we have received your saying and an email from adidas saying ignore

Hi, this is the 4th letter I have now had from dwf regarding a debt I apparently owe adidas from October 2021. I have sent a screenshot to dwf from adidas saying to ignore dwf but they do not give up. All items were returned on October 2021 and after checking tracking , returned to sender January 2022 which is not the case as I have not had anything back. This is why adidas are chasing me . Is there a way I can report or anything? 4th letter is different heading to 1st 3 .