pip claim

In jan this year the dwp stopped my dla with no prior warning, after contacting them they told me i hadnt returned my P.I .P form {i never recieved it} so i requested a new form and sent it recorded delivery ,waited for a reply , i rang them again , they said they still had.nt received it ? i then went online to check that it had been received and signed for , it had . I rang again even sent an email showing the receipt to prove it had been received/signed for 4 imonths later i am still waiting . If you can please advise me on what i must do it would be very helpfull . I have a brain injury which affects cognitive memory and balance . I served for 11years in the Royal Engineers
thankyou

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