"As an O2 business customer, I tried upgrading my phone but shamefully disconnected from the network without any reason . I think somebody is trying to sabotage my business . 72 hours passed . Engaging with customers service is like knocking your head on a brick wall . I think staff should read notes left on system before making assumptions . I am very disappointed and horrified . Time to leave 02 for good .worse. Customer service and network ."