Child custody

Hi! My husband has a joint custody with his ex wife. We only get to see our son on every Saturday from 2pm to 6pm as per court order and his ex wife wouldn't let us see him more time either. And today we didnt fetch him because he was unwell, but we went to her place because we want to visit our sick son. But she totally ignore us. We waited like 3houra today. All msges and call was not answered :( What you guys think we should do? Is going to court and get a new frtsh court order so that we can atleast get our son for sleepovers and more time? We have go thru this for almost 3years... And all these years. We only get 4hrs per week.