Vodafone had to fix a technology fault that was affecting some customers last night.
A spokeswoman for the telco giant confirmed some mobile customers may have experienced problems adding new data to their accounts because of a fault in the processing of data orders.
"This issue was brought to our attention very quickly and we are currently investigating the cause of the problem."
All our customer care staff have been fully briefed and we encourage any customers experiencing problems to please get in touch.
"The issue was being handled as a high priority, she said.
"We are very sorry for any inconvenience."
The issue was fixed just after 9pm - about two hours after some customers started experiencing problems.