The supermarket set up its virtual network, which piggybacks a signal from Vodafone’s mobile towers, in July 2013.
Under a virtual network agreement, carriers such as Vodafone can opt to rent out some of their network capacity to another party so that it can avoid the high capital costs associated with setting up their own infrastructure.
Its rivals Tesco and Asda have set up their own similar services that run on O2 and EE’s towers respectively.
However, where Tesco Mobile boasts four million customers, Sainsbury’s had only managed to attract 150,000 to its network.
It is understood Sainsbury's and Vodafone pulled the plug on the joint venture after disagreeing over the future of the service.
Most of the customers affected are on sim-only pay-as-you-go deals and Sainsbury's said they will not be able to top up credit after November 14.
It is also advising them to use credit by January 15 2016, although it...