Vodafone Qatar has said its engineers are working through the night to ensure that the network was "reliably restored".
For the second successive day on Tuesday, Vodafone subscribers faced network-related problems even as the company said 2G services had been partially restored and efforts were on to achieve further progress.
Global network experts arrived in Qatar on Tuesday morning to fix the problem, the company said, adding that a compensation plan would be announced within 24 hours of service restoration.
The outage began around 3.30am on Monday and left many Vodafone customers without access to voice calls and data services.
In a statement on social media last night, Vodafone Qatar said: "Our engineers are on-site all night again and we will be conducting critical stabilisation work to ensure the network is reliably restored."
Earlier, the company said it deployed additional head office staff to its retail stores and call centres to assist customers, and online chat agents were also available to answer queries. "We assure you we are doing all we can to restore all our services," it said in an earlier update on social media.
The 2G network was partially restored during the day, allowing customers to make calls in some areas to other Vodafone numbers and international numbers, according to the company, which said efforts were under way to get data services back up on 3G and 4G.
Meanwhile, the company said in a press statement that their team "worked tirelessly" through Monday night to resolve the technical issue, which was triggered by a routine upgrade as part of the network modernisation programme.
"We have made progress on restoring 2G voice services and now the focus of our entire team is on restoring full connectivity across our network with the aid of global network experts who have arrived in Qatar on Tuesday morning," the statement said.
"We are working fully with all relevant stakeholders to address all requirements."
Vodafone also said they would be announcing a compensation plan within 24 hours of service restoration. As part of the compensation, all balances that expired on Monday night would be returned to customers in full with a new expiry date of July 28. Moreover, balances scheduled to expire in the next 10 days will have their expiry date extended so they remain valid until July 28, the company said. "We are deploying a full communication plan and intend on keeping customers updated on an hourly basis via all our social media channels," it added.
Meanwhile, Vodafone Qatar CEO Ian Gray expressed disappointment over the outage in a video message on social media. Noting that he was “sad and frustrated”, he apologised to customers for the network problems they had been facing.
The network was restored but the back-up caused problems, he said. “People from the world over connected to help Vodafone Qatar rectify the problem," he said.
"The main focus is to get the system working and to give the service that customers want,” he added.
On Monday, the Communications Regulatory Authority said it had initiated a full investigation into the outage of Vodafone Qatar’s network.