Rift won't close

My character is a lvl 8 rogue & I'm having trouble with the rift near Redcliff. There are bandits & wovles near the rift as well.

I've tried closing this rift at least half a dozen times. My problem is that the hand gets no response from trying to disrupt the rift. We kill the 1st round of demons & still no disruption to the rift. My hand moves around everywhere. on the words & around them. Nothing. It's like that rift has frozen in one sense. Yet more green stuff spurts out & 2nd wave of demons spawn. Now they are really strong. Then the 3rd wave spawns, which sees my team & myself dead, because they are now too powerful.

Hey! I'm playing in casual mode why are these demons so powerful? I don't know much about tactics.

I even tried to close the rift from a different angle & in stealth mode. I went around to the top of the rainfall & tried to attack them from up there, but those cunning demons could sense I was there and pounced on me. They jump & pounce very well.

I don't know if having bandits near the rift upset my game or not. I just can't understand why the rift can't be disrupted after the 1st wave of demons is killed. Crystals form etc. but the rift is frozen.