Customers of Smartbox sister company Tec Rentals could miss out on keeping their equipment free of charge if they sign new hire agreements.
Tec was the third arm of a venture run by Kate Venables and Neil Orton, which also included screen media company Smartbox and Vision Leisure Services.
The other two arms folded in late October owing customers hundreds of pounds in advertising revenue.
Tec hired equipment direct to licensees unlikely to have been able to gain finance through third parties.
If no licence is in place, all agreements with sole traders and partnerships are potentially unenforceableConsumer Credit Trade Association regulatory policy manager Graham Haxton-Bernard.
Julian Barfield of the New Inn in Talgarth, Powys signed an agreement with Tec Rentals and Smartbox on 4 July 2005 and agreed to pay £75 a week for a Smartbox, monitor and plasma screen. He was entitled to receive £35 a week from Smartbox for displaying adverts but was owed over £2,000 when it folded.
However, the MA has since discovered that Tec Rentals did not gain a consumer credit licence (CCL) until 12 November 2005.
"If no licence is in place, all agreements with sole traders and partnerships are potentially unenforceable," said Consumer Credit Trade Association regulatory policy manager Graham Haxton-Bernard.
"Consumers could be relieved of further liability and be able to keep goods."
The company's first move was to attempt to get Barfield to sign a new legal finance agreement with Churchill Finance Group, with the incentive of a reduced weekly rate of £35.25.
"The new agreements are offered as part of a re-finance of Tec's book through Churchill Finance," said Orton.
"The lower rates reflect the loss to the customer of the Smartbox channel and its other services."
When Barfield refused, Orton wrote to him: "In the circumstances I feel it is appropriate to allow you to keep our equipment free of any further charge by way of compensation."
The company now claims this offer has been withdrawn after Barfield vowed to press ahead with legal action to get back all the money he has paid Tec so far.
Another Tec Rentals customer, Barry James Russell of the Londonderry in Oldbury, West Midlands said: "We are still using the equipment and they are sending out discs, but we are not paying for it."
Directors deny claim
Orton claims the consumer credit licence issue is not important.
"This rental agreement was brokered for Tec Rentals through Mercian Leasing and Vision Leisure Services, both of which had the necessary CCLs. Tec did not negotiate with the licensees itself."
However, one consumer credit expert said: "It is irrelevant whether or not the deal was brokered through Vision Leisure Services or Mercian Leasing. When the agreement was put on the books of Tec Rentals, it became illegal as no licence was in place."
Vision Leisure Services' licence also lapsed between 6 September 2005 and 18 November 2005.
OFT warning to unlicensed businesses
An OFT (Office of Fair Trading) guide for businesses warns: "Unlicensed trading is punishable by a fine, imprisonment or both. If any customers were to default on a payment, you would not be able to enforce a credit agreement made whilst unlicensed."