A cut fibre stops sales. A backup link brings them back in seconds.
At every site we install a router with a mobile module and a SIM. If the primary line fails, traffic switches automatically to the mobile network and returns when the primary is restored. The switchover is automatic — nobody on site touches anything.
Model choice depends on location: where coverage is good and the network is quiet, an LTE device is enough; in urban areas with congested cells we use a 5G model that combines more frequency bands at once.