Yes we have had other posts saying the independents give better deals.
In the end it makes sense to go where the better deals are.
Sometimes O2 retentions do match deals too.
You don't need to cancel and lose your number.
Upgrade instead.
Get a screen grab of that deal and perhaps ring back and ask to speak to retentions. Show them the deal.
Have you checked out Carphone Warehouse.
Info about e2save. They are not owned by O2.
"Because e2save is a trading division of The Carphone Warehouse limited, this means we have an amazing choice of handsets and tariffs across all major networks."
I understand your need to vent. We all do at times.