How can I force my ex to pay his contribution to my son's student finance?

Questioner

My son is studying full time and receives student finance. He received 300 euros per month the first few months, now only 200 euros per month and my ex has to contribute 100 euros per month. But he does not do this. 'If my son needs money he can ask for it' but does this work? Can I force him to pay his contribution? If so, where and who can help me with this?

Lawyer

How old is your son? The mandatory maintenance stops at the age of 21 and the contribution of Duo is fictitious and cannot be enforced other than in a rather nasty way by stating that the relationship between father and son has been permanently broken off or because of agreements that you both made in a covenant.