Help needed with ESA etc - very anxious

Hi Ive just recently joined and was hoping for some advice. I will try to explain all sorry if too long winded.
I was originally on Incapacity Benefit and in 2011 after re-newal was put on ESA in Support Group. In March 2013 was sent a letter and a form stating my benefit was changing from IB to ESA I queried this and was told the letter was wrong but right at the same time? Anyway form duly filled in and sent back. As I had not heard anything I gave ATOS a ring three weeks ago to be told by an advisor that "I was to be sent for an Assessment" when I explained that amongst other things I had extreme agoraphobia and anxiety and never left the home the advisor stated that my GP clearly did not think so as he had put I was capable of attending and therefore they did not see that I had agoraphobia etc at all. This upset me greatly. During the following few days I rang them again and queried this and this time the advisor said the file would come back from my local centre and be looked at again (would take 24 hours) and I called GP surgery and was fully told what they had written on the form, which clearly contravened what ATOS had previously said, they had in fact stated a home visit for assessment be necessary due to my agoraphobia etc.
I informed ATOS a few days later what I had heard from GP and they said they would get file back I stated it had already been requested (no it hadn't as the staff member had gone off sick) - during the conversations with this particular advisor I was informed that she felt that an error had been made
a) I had the wrong letter back in March
b) I was not entitled to a home visit as I did not come under the category of Severe Disfunctional Disability - I was able to function in the home and therefore could come for an appt.
c) She felt that an error had however been made as ATOS had sanctioned my claim for a further 18 months back in May but the DWP had returned it to them so therefore they were asking for more information and that meant an Assessment which I would have to attend.

During the course of our conversations over the following week she said that she thinks my claim would have to be re-assessed there end all over again - Im taking that to mean that they are looking at it from the start again as if they had never agreed it months ago????

I have since heard I have been allowed a home visit assessment but will have to wait as there is a backlog of appointments.

I am so anxious about all of these problems - I always worry so much when I have to re-renew so have been anxious since March and now this on top.

Have tried to get advice elsewhere - ATOS told me to ring DWP for an explanation - DWP said that this was an ATOS problem and take it up with them, and advised I get outside help - CAB said they would speak on my behalf but they would normally do that whilst I was in the office and as I wasn't in the office this would make it difficult - I asked ATOS if they would speak to CAB to get this sorted and the person said we don't take complaints and anyway it was sorted. Now CAB have said that as Ive now been allowed a home visit this was good, Im still receiving my benefit which is good and wait for the outcome of the assessment.

Im just not sure if this whole scenario is normal? Can DWP refuse it after ATOS said yes? Is it normal for them to look at the whole case again? What does Severe Disfunctional Disability mean?

I don't mind informing you that I do have severe anxiety, depression, agoraphobia, arthritis/fibromyalgia

Another point is I do have help with our debts from a local authority money advisor and they have stated I should not even be getting the benefit as you are only allowed contribution based ESA for 12 months whether in the support group or not and thereafter it goes to Income based and as I have a partner who works I should not by rights be getting it.

Im so sorry there are a lot of points there Im just so hoping you can help.
Looking forward to hearing from you
PS Im also worried about the assessment Ive never had one before and have heard horror stories about them

Yes Im very pleased about being given a home visit - what can I expect at the assessment?

My one main query is that ATOS after looking at my form and getting further medical info from my Doctor in May sanctioned the benefit for 18 months further but they said DWP returned it in June

Is this normal?

So even though ATOS originally sent me the form and letter in March and they made their decision in May after evidence for me to have benefit for a further 18 months, DWP still have the final decision?