Help...grounds for child abandonment?

my ex partner has not seen his children for 2years,no written /verbal communication,no presents/cards, no financial help ever since born. But he was granted parental responsibility2yrs ago!! False allegations about me where made by him and he has to return2court if he wants to c children he has not done so in2yrs as he knows the judge will condem him .can i get this annuled as he has played no part in there life since this.how do i go about it,will a judge grant this