DWP incompetence ref ESA : backdate??

I wonder if any of you good people can help me regarding an ESA claimant. (a bit long winded but bear with me)
My client has complained that her ESA kept getting stopped due to her fit (sic) notes not being received by the DWP. The DWP even claimed not to get sick notes that i had sent to them personally.
The client came in a month ago in a right state saying her ESA hadnt been paid and she showed me a recorded delivery slip proving postage of her last sick note.I called the DWP for clarification and they told me that this time her ESA had stopped as she failed to attend a WCA and had nothing to do with medical certificates.
I asked my client refgarding her WCA non attendance and she informed me that she received a call on the morning of her WCA from medical services postponing it as the medical practitioner could not be available that day. They apologised and said they would be in touch to re-arrange. Unfortunately my client could not provide evidence of this call and I wrote to the DWP on the 3rd of may 2011 explaining her good cause for non attendance (and that she had been to several medicals ref her time on IB) and it wasnt her fault the medical was postponed, and also to request her ESA to be backdated.
I was told on the phone that a DM would look at my letter, contact ATOS for confirmation that they had postponed the WCA and re-instate the benefit once ATOS had confirmed they had cancelled.
I called DWP today and (yep - you guessed it) they have no record of my letter and her ESA claim was closed weeks ago as it was said to be “dormant”.
Can her claim be re-opened and backdated to ensure she does not lose out on her money? If not can she be compensated as none of this appears to be her doing, just DWP losing sick notes, letters ETC. She has been borrowing money left right and centre until her backdated ESA paid but now its a closed claim its not looking good.
Any advice would be appreciated.

If your client has a sympathetic MP I’d also be trying to get him/her to throw the book at them. Its ofen surprising how an MP’s involvement turns up missing records or leads to an apologetic climb down.

I should put in a formal ‘‘subject access request’’ to ATOS requesting copies of relevant computer screen printouts as concern the relevant date as relate to your client, copies of any written records, including copies of any telephone records that relate to your client for the date in question. I wuld copy the ESA department into your request, making a statement as to your reasons for requesting copies of the records, and I would insert a paragraph asking whether or not in these circumstances ATOS will be requesting the statutory payment of £10.00 for their provision.

ATOS have 40 days to provide the requested information before they can be reported to the information commissioner who will then take up the matter (upon your written request) upon your behalf.

This may sound like a sledgehammer to hit a nut, but sometimes you have to get a little creative with the DWP in order to obtain the required results.