Esa and Suspended Carers

I’ve received Esa since 2012, and my partner got carers as well as he is my carer due to my health.
He started working Aug 2016, until May 2017 he still got Carers. They notified us that due to his wage he was ineligible anymore, and after going to a jobcentre appointment, where we gave all the evidence they asked for (wage slips and bank statements) we asked to have the claim cancelled.

We recently found out (from esa reassessment letter notifying us of current esa rate we get) that we were still getting carers deducted from my esa. We rang esa and after 4 days were told to contact carers.
I spoke to them and they said that the claim hadn’t been cancelled, it had been suspended instead. They then told us we had been sent forms to fill in to stop the deductions from esa, we haven’t ever received any forms.
Yet it was confirmed that the whole time we’ve been losing carers from my esa. (62.70per week then £64.60 per week) due to their error.
I asked about back dating and we were told we now have got to get all my partners wage slips (he stopped working 30/12/18, as we are moving to another city, and my health has worsened) plus bank statements and another form sent in. I argued that on their own policy it states we can cancel a claim or if a claiment isn’t in contact then it should be cancelled by a dm.
But it was still deducted as they didn’t cancel the claim as requested (or via lack of communication) as the dm hadn’t looked at it. The limit is 1 month of no communication on suspended cases, equals termination. Yet it wasn’t done that way either.
It was blamed on a back log.
Either way since May last year we have still been having carers deducted from esa, but not paid us. We received no carers, yet it was still taken from my esa.

Can I get any of the money backdated? Or refunded as, as far as I’m aware, if you don’t get carers paid it shouldn’t be deducted