An upgrade to the Freeview digital television system has rendered thousands of digital set-top boxes useless.

The upgrade is designed to allow for more channels but has prevented six models of set-top box, made by Bush, Daewoo, Labgear, Portland and Triax, from working.

A list of models affected is available on the Freeview website. Freeview is advising owners of the Bush, Portland and Daewoo products to contact the manufacturers by phone.

When contacted, the Daewoo helpline told us that “the company that’s responsible aren’t offering any compensation whatsoever”, and offered to supply a replacement receiver for £19.99.

When asked which company was “responsible” for the problems, the helpline pointed the finger at the Digital television Multiplexer Operators Limited, or DMOL.

Similarly, the Bush helpline pointed the finger elsewhere. An operator said that the company would not replace the now useless product, explaining that “it’s not a box problem – it’s Freeview … they have changed the transmitter range. That’s the reason it cannot work”.

When asked whether the problem was caused by DMOL, a Bush spokesperson said that the affected Bush product, of which fewer than 2,000 units were made, had been tested and approved by the Digital Television Group prior to going on sale.

Staff at Daewoo failed to respond to our phone calls and emails asking for comment.

When asked who caused the problem, Rob Farmer, director of marketing communications at Freeview, said that DMOL “needed to make these necessary changes” to the broadcast system.

He added that “while Freeview did not request” the update, “DMOL’s plans were conveyed to Freeview, the manufacturers and retailers and we worked together to optimise the roll-out plan”.

He said that so far Freeview has received around 2,500 calls from affected customers, and that “together with the manufacturers we’re doing all we can to help viewers find the best-value replacement box”.

DMOL Ltd does not provide a contact telephone number or email address on its website, which directs customers to the Digital UK telephone helpline.

In the meantime, affected customers are left out of pocket as well as unclear as to who is responsible for their predicament.

“I’m kind of furious, really,” said Mike Parsey, whose Triax receiver has been left useless by the upgrade. “I can afford a replacement, but there are an awful lot of people for whom the replacement box and installation is an awful lot of money.”