At first glance I would have assumed it was some kind of a joke but it seems Dial a TV do exist and do actually write poorly worded semi-threatening letters like that which breach data protection rules.
Seems someone’s managed to rump ’em for some kit by selling them a Cock and bull Balls story, they’re basically the lowest of the low end credit providers who lend TVs, Sofas and Mobiles to the unemployed and people on low incomes. Their underwritting rules must be non existent so losing a couple of TVs must be SOP for them.
Ignore it, if they become persistent send them a cease and desist letter.