Jobseekers Allowance not received - what to do?

I have a relative who made a claim for Jobseekers Allowance. they got a job 10 days later but still should have been entitled to the allowance for that short period, which would then have entitled them to housing and council tax benefit too. They received their P45 and a letter confirming they had signed off, but no benefit money for the period, this was about 8 weeks ago. Letters have been ignored, there is no way of contacting by email, in phone calls (very difficult and lengthy) they are told they will be phoned back, but they never are. What is the next step? the local jobcentre wont deal with it but refer them to the admin centre, and the admin centre won't allow access to the names or contact details of a manager. It might seem a small and petty period, but in financial terms together with the housing and council tax benefit entitlement, equates to about �200, which they cannot afford to throw away. Any JSA knowledgeable person able to advise how we should proceed.