Rotating crown and abutment: advice?

I have cemented a crown on an implant with long term temporary cement. When I screwed the abutment, the final screwing with the hand screwdriver rotated a little the abutment - so that I cannot fix the crown in the right position. After minutes of 'ultramilimetric positioning' I found the right position, and I cemented the crown (no , it is not a screwed-retained crown). Now the patient came back to the office because the crown is rotating. I have tried to take it off, but it didn't come out and I didn't want to force very hard. What solutions do you advise? 1. take off the crown and 2. make the abutment to do not rotate? The implant brand is Anthogyr.