The first step is to take legal advice. It is important that you do not allow maintenance arrears to accumulate. Often matters can be resolved without having to issue legal proceedings.
If, however, the matter cannot be resolved without the assistance of the court there are number of legal remedies available. The most commonly used is an Attachment of Earnings Order. Once the order is made it is served on the debtor’s employer who deducts the maintenance from the debtor’s salary every month before it is paid to the debtor. An attachment of earnings order is not effective against a self-employed person.
Where you have the debtor’s bank details you are able to apply for a third party debt order. The order is served on the relevant bank or building society which will pay any arrears to you, providing there is sufficient funds in the debtor’s account(s). Equally, you can apply for a charging order, the effect of which will be to give you a charge against the debtor’s property. The difficulty with both of these remedies is that they can only be made in respect of arrears and do not provide for maintenance payments going forward.
Ultimately, you can apply to the court for your ex-partner to be sent to prison if he or she continues to refuse to pay maintenance. Custodial sentences are used only as a last resort.