Vodafone has been banned from advertising its broadband service.
The company has come under fire for misleading customers over speeds and reductions in bills and, as a repercussion, is no long allowed to promote the service.
Vodafone has said it's disappointed with the Advertising Standards Authority's (ASA) decision - which was encouraged when it received complaints from customers and rivals such as BT - and believes it "misunderstood" the offer.
A spokesperson for Vodafone told the BBC that the guarantee "is still unmatched in the market as no other major brand offers a promise like this across their entire range, nor do they apply discounts directly to customers' bills if they don't deliver".
Vodafone found itself slapped with complaints after their television and radio advert featuring Martin Freeman stated: "Vodafone guarantee your home broadband speeds or money off until it's fixed" after his internet cutout midway through a game.
The Vodafone website stated: "Our Ultimate Speed Guarantee means you get the best broadband speed available to you, or we'll give you a discount off your monthly bill until we can get you there."
But ASA think consumers may interpret that advert to mean that Vodafone would prevent any buffering issues and reduce the bill if they can't.