Hi Mikey
I'm sorry, but there's very little I can say. Receiving information from the DWP via the post office is problematic, and I can't tell you how long you should wait before writing again.
Do you have anyone else who could be with you and call the DWP? You would have to confirm your name and listen to a couple of questions to which the answer is "yes", and then the other person could speak and find out if the form has even been sent out. Your letter may not have even been processed yet.
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
