O2 advised channel partners to put through only very limited business for four days this week because of a major upgrade to its billing system.
The systems upgrade started Wednesday (August 6), and ends Sunday (August 10).
Dealers have been advised not to process new O2 connections, upgrades (checks or confirmations), tariff changes or additional lines until the deadline passes as there will be a delay activating them. They cannot port numbers either.
O2 advised dealers to submit requests as early as possible before the Tuesday August 5 deadline in order to minimise disruption and to guarantee connection.
The only processes that go unaffected are new O2 business customers credit checks and corporate connections of 75 handsets or more.
An O2 spokesman said: "We are upgrading one of our billing systems to primarily provide additional functionality and system resilience.
“The additional capability will benefit both us and our customers."