He will avenge them speedily. There is no problem with God's care for us. The reason prayers are not answered is not due to his disregard for us. Among other reasons, some prayers are not answered the way we want them to be answered because when we pray we ask amiss that we might consume the answers we seek upon our lusts. It takes faith towards God when you pray for your prayers to be answered.
Many people never get prayers answered because they beg when they pray.
They tell God all the reasons He should answer their prayers and they beg and beg Him to do it, even weeping. In these last days people are losing faith rapidly. Jesus warned us this would happen by asking if He would find faith in the earth when he comes. Now, Jesus' coming is referred to in this parable. There are two comings of Christ.