Hi Bell
Welcome to the forum, you might want to have a look at the following FAQ which explains where everything is.
Welcome to Benefits and Work .
I've moved your post to its own topic, we ask members not to post their questions in other member's topics as it can lead to the wrong advice being given or taken.
You do need to find the RD slip as without it, it is your word against theirs and you will not win.
We advise claimants when sending in their forms to contact DWP to check that they have received it, even though you can check on line that it has been delivered.
You can apply for a MR and explain when you returned the form but they may ask for proof of delivery, this has happened to me a few times but I always staple the RD slip on to the copy of the form so as not to loose it, I also write the RD ref number on the form just in case it gets detached.
Gary
