In many areas O2 is oversubscribed for the amount of bandwidth available.
Building new masts is a long term and expensive process.
There are ways to increase bandwidth which are much cheaper, but I've seen no effort to do so, probably down to lack of investment by Telefónica who have been trying to get rid of O2 for years. Not sure if things will change with the joint venture with Virgin. However, I keep hearing of investment in fibre broadband and nothing on the Mobile side of things
This is not O2 and we are all customers here similar to yourself and cannot answer account type queries.
