Millions of O2 customers were left without data on Thursday, with some also struggling to make calls and send texts.

While there are 25 million people on the O2 network, the outage also affected customers of GiffGaff, Lycamobile, Sky Mobile and Tesco Mobile, which plug into O2’s infrastructure. It is estimated that the outage – which lasted for much of the day – affected 32 million people. O2 said the disruption was caused by a software issue.

By Friday morning the company said its 4G network had been restored.

“Our technical teams will continue to monitor service performance closely and we’re starting the full review to understand what happened. We are really sorry for the issues yesterday,” the company added.

The impact of the prolonged outage was profound for some small business owners and workers who rely on data to carry out their day jobs. This includes taxi drivers and market stall owners who use O2’s network for handheld payment terminals.

Compensation offers

To apologise for Thursday’s disruption, O2 is offering its customers the following compensation:

• Pay Monthly, small and medium-sized business customers and mobile broadband customers will see their accounts credited with two days of monthly airtime subscription charges by the end of January.
• Pay As You Go customers will receive a 10% credit on a top-up in the New Year. 02 will let customers know when it is available.
• Pay As You Go mobile broadband customers will receive a 10% discount on a ‘Bolt On’ purchase in the new year. It will notify customers know when this is available.

What happens if you are unhappy with O2’s offer?

If you were adversely affected by O2’s outage, you can lodge a complaint directly to O2 via its website. To strengthen your claim, you should submit copies of any receipts for costs that were incurred as a result of the outage.

If you are unhappy with O2’s response or the complaint remains unresolved after eight weeks, you can submit a complaint to the Alternative Dispute Resolution (ADR) service. This comprises of two ADR schemes CISAS and Ombudsman Services: Communications. It is worth noting that O2 is a member of the latter scheme.

Ofcom, the UK’s communications regulator, does not get involved in individual cases. However, its website includes advice for those who wish to lodge complaints about their mobile phone providers.