Pip may owe me money

Hi. I had my review and my pip money has now gone to enhanced rate. It says on letter pip may owe me money.  I contacted pip and they said it had gone to debt management some time ago and they had not heard back from them. I contacted debt management on 2 occassions and both said they had responded to the email sent from pip on day they recieved email. They confirmed I do not owe any money.

So I called pip again for them to say they not recieved a response from debt management... I repeated that debt management confirmed they responded. They then said a case worker is assigned to my case and that money will be in my account in 5 working days. Its day 9 and still nothing. I'm fed up of being told from pip to call dm and dm saying call pip. I feel like I'm being pushed back and fourth. Anyone have any advise please. Thanx in advance