DWP has specific guidance for this situation and in all likelihood you are now on the Unacceptable Customer Behaviour database.
"Everyone has a vital role to play in ensuring that the database is populated and used effectively. The database will only be useful if it contains up to date, accurate information. It is absolutely critical therefore that members ensure that they report all incidents.
Sadly, we know that not all incidents in DWP are reported. This has often because members felt they were not afforded time to complete the reporting documentation; that they believe they should tolerate abusive behaviour as part of the job; that they feel it would show an inability to fulfil their job role; or simply did not think that the incident warranted reporting because the threat was to someone other than themselves or was just not serious enough to be reported.
It is crucial that any incident is formally reported and DWP and JCP guidance is clear that anyone involved in an incident is given time to complete the report. The fact that you personally do not feel upset or threatened by inappropriate customer behaviour does not mean that you should not report it. The customer who shouts at you in a telephone call could potentially assault a colleague in a Jobcentre if your colleagues are not aware that the customer can react angrily."
http://www.pcs.org.uk/download.cfm?docid=45173D85-84FD-4D3E-8C68083256E7FD89