unable to load books onto Kobo - get message URLLink damaged or corrupted - how do I solve this problem

Recently had CP in repair shop and machine had to be re-formatted.    Purchased some books on May 2nd and cannot get them to download to my Kobo, as each time I try I get the message up that they cannot download because URLLink(12).acsm  is broken or has been corrupted.     Please help as I have eleven books to download and I don't want to lose them.