The operator of the mobile carrier “au” will cut millions of customers’ bills to make up for disrupted service last month. Besides the inconvenience of being unable to communicate or receive data, the disruption meant users could not make emergency calls, prompting discussion of technical changes to address such situations.

SoftBank’s mobile service outage affected millions of users in many parts of Japan on Thursday afternoon. Sweden’s manufacturer Ericsson apologized and said its equipment fault was to blame for the disruption.