direct debit refund timescale

[vanordinaire]

I rented a council lockup last year and paid the rent by monthly Direct Debit. I gave up the tenancy in October but was advised by the council not to cancel the direct debit as they would use it to pay rent for the notice period then cancel it themselves. I was checking bank statements today and found they had forgotten to stop the direct debit and I have overpaid them by a few hundred pounds.
I spoke to them this morning, they admitted their mistake, agreed to cancel the DD immediately and send me a cheque for the overpayment within the next 3 weeks....WTF.. I asked them to rectify it immediately but they've said that's not their procedure.
Is there a time limit for them to rectify a mistake like this or would I get a result quicker by asking my bank to sort it out under the DD guarantee scheme?

[Mercury00]

Ask your bank. I cleared the finance on a car and VW took another payment, I went to my bank and they had the money refunded straight away. No hassle.

[CarlosFandango11]

Mercury00 said:

Ask your bank. I cleared the finance on a car and VW took another payment, I went to my bank and they had the money refunded straight away. No hassle.

This.