Carers deducted from UC 9 months after migration

Hi
I'm just checking here really, I've just had a letter from UC stating that we have been overpaid by £3248.00, due to my getting Carers Allowance, 9 months after my partner and I migrated from ESA to UC.
What I can't understand is that we made it clear that I was getting CA when we did the Migration, and now they have deducted £360 pm from us and want us to pay back the overpayment.
I know it sounds a bit daft but I can't remember how we did our claim, whether it was online or in the local office.
Also has anyone else had this sort of problem.
Any advice would be greatly appreciated.

Hi David
If you mean on the breakdown, then there is a section that says "Carers, because Paul was caring for someone £201.00.
So they must have known to be putting that on there, surely.

Apologies David
I will say that the Carers element, is nowhere near the same amount as I am getting from Carers allowance, about £160.00 difference, but they are taking the full amount of Carers £360.00, from our monthly payment now.

Hi David
I checked the payment section and it does have a carers element on there from the date we migrated at a rate of £201.00pm.
I've spoken to universal credit, and they say that we told them about the CA but because they got a late notification from Carers allowance at the time, it caused the overpayment.
I wouldn't mind, but we did all our bit correctly and now we have to not only have to take a drop in money but we have to be even shorter on cash because of someone else's mistake .