WTF - what a load of cobblers. Don't shoot me but I processed Income Support for many years and the way she dealt with you was appalling.
What office was it? I am a senior manager in jobcentreplus and if I found out my staff were dealing with customers like that then they would get the sharp end of my tongue.
Sorry but bad customer service riles me especially in an organisation that are meant to be there to help people.
I know it doesn't help but the best thing you can do is contact the line manager of that processor. each team has a line manager a grade above them. pending that each IS section has "HEO" you could complain to. the manager up frm them is the "SEO" and then it would be the District Manager.
There should also be a customer service manager.