Can debt management team take old debts already paid through UC each month

I was awarded enhanced mobility backdated to nov 23 advised by appeal officer that i would be paid in five days. I waited the five days nothing. Contacted the team and was advised its gone to debt team to see if they want to take anything. I asked how can this be as this is a disability benefit which is something I should have had every month and it should have never been a lump sum. They dont know what its for or why. I advised that they should manage customer expectations and let us know that this is the case instead of already waiting two years for a decision to then be told we will receive a payment in five days and then get nothing but having to phone another number that your on hold for ages. If your in financial hardship and already paying the debt through UC and have done for years why should this be taken.