I don't know what kind they had but if it is the kind that screws on to the trailer you might suggest they get one with the 90 deg angle plug on the trailer end if they didn't have one before.
I know the link below is not the right cord for their use since it is a 30 amp but it is the style I am talking about
http://www.campingworld.com/shopping/item/30-amp-30-right-angle-locking-rv-cord-set/72104&utm_source=google&utm_medium=cpc&scid=scplp72104&sc_intid=72104&affiliateid=6313&gclid=EAIaIQobChMIy7D7icnS1wIVAdlkCh3ZAwLGEAQYBCABEgLi0_D_BwE