PIP/DLA or lord Lucan…..

I have a client who was overpaid DLA allegedly. I wrote to DLA to ask for an MR in July. No response.
I called DLA to chase it up and was politely told to go away and speak to PIP, as they were now dealing with everything, including historical DLA stuff.
I called PIP, and guess what? They said they had nothing to do with DLA, they only dealt with PIP.
I called DLA again, and they tried to put me through to a manager, who then refused to take my call and hung up…..

Can anyone either : A , Give me Lord lucans address as I think I may have more luck resolving this with him, or
                      B, let me know who is actually responsible for this kind of issue? Nobody wants to take           responsibility or even talk to me. Im looking at a complaint.

Any tactics/help would be appreciated

Thanks

Complaint directed via the local MP. This route means the DWP have to respond within a time limit.