I imagine it is like most organisations, where i work in IT we have few difficult customers, they shout the loudest and tend to be the ones that are most illterate and bad mannered.
I am suprised that the staff are paid poorly at the sharp end. The average wage in London must be around £28000 with the inner London allowance, i can't believe they are on less than that.
Keep IT simple the more choices in technology the more there is to go wrong.
If you do have bad suppliers or third party suppliers like BT you must have a resilient way of escalating ad resolving your issues.