If you think that you do not owe all or part of the money, you need to contact the organisation who is claiming the money from you e.g. your local council, child support agency or the magistrates' court. The organisation concerned has told the bailiff or enforcement officer that you owe this money, and it is not up to the bailiff or enforcement officer to decide that you do not. You should make sure that you have the relevant account number or reference number to hand when you contact them.