My apologies for the late response. I understand it can be a bit expensive, however we find it important in the first place that people can get good results with their machines, so of course there are some options of fixing it yourself as well and I want to try and think along here.
You could maybe 3D-print a puller wheel with a similar material, like TPU for example. Or you could just replace the rubber part on the existing puller wheel. That could be anything similar to a ring of silicone (which can be casted into a suitable shape to fit on there).
Another idea that just came into my mind; you could maybe remove the silicone that is still left on the puller wheel, and just replace it by winding silicone tape around it, until you get a similar thickness.
Maybe with a DIY replacement the grip/clamping strength will be a bit different, you can adjust this by tightening the bolt/nut with the spring at the back of the puller mechanism (this determines the clamping tension).