Request for a paid up letter from rcs Edgars which they never sent

My Mother has been asking rcs Edgars(account number ***) for a paid letter as she has settled her account for two weeks now she went to an Edgars store on two occasions to request for them to call the relevant department to ask for the paid up letter she spoke to someone called Debeney who promised they will send the letter via email which they never did two email addresses where given to Edgars rcs to send the paid up letter to which they never did, a further email has been sent to Edg******* to request for the paid letter nothing has been sent yet so clearly Rcs does not care about thier customers or respect them.