Speak to them first and see if there is a legitimate explanation. Maybe their circumstances have changed and a reduction in maintenance for a period of time could be a helpful option. If there is no maintenance being paid and there is no effort to communicate a reason, the CMS or a lawyer can help. A lawyer can contact your ex and try and explain that it is better to discuss the situation than to ignore it. They can then carry on this line of communication for you in hope of finding a resolution. Alternatively, the CMS can be informed and they can assist in reaching a resolution to recover the situation. Unfortunately, in our experience non-payment happens regularly, and not only as a result of hardship, but also due to a deterioration of relations between ex partners.