Hi
Did you cancel the direct debit with the bank before DW claimed the €415? If you did then your bank are at fault for paying them and it is up to them to repay you. Whatever you do, do not let DW away with it. If the refund is not with you within at most 2 weeks follow it up.
Has
IBB connected you? If they have what is the quality of service like? Hopefully it is better than DW and hopefully you will not be disappointed.