Hi Pipkin9
Welcome to the forum.
You might want to have a look at the following FAQ which explains where everything is;
www.benefitsandwork.co.uk/guides-for-claimants/faq/forum.
Your post is a bit confusing as in the title it states Change of Circumstances but in your post you requested a claims form, unfortunately there is a big difference between them.
If you contacted DWP and reported a change of circumstances then your claim should be backdated to the date of the phone call.
If you contacted DWP and requested a claims form then your claim will only go back to the date of the decision.
Gary
