Hi Jack
I can't tell you what the call is about. They may just want clarification on something.
When they ring, confirm the reason for the call before you answer any questions. Write down the name and job title of the person making the call in case you have any cause for concern afterwards. At the end of the call, make sure you ask them what happens next.
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems