Re: my bees are being robbed 3 days after install
Your bees have a good shot at survival.
You did the right thing to block that hole, having a hole near a feeder is never a good idea. A newly installed package takes a while to sort themselves out, and until they have their own identity as a hive they are easy pickings for robbers.
So in addition to blocking that hole, shut down the main entrance to the minimum they need for coming and going, plus cooling. Have the hole in the middle nearest the biggest number of guard bees, not at the edge. If robbing still continues, remove the feeder. It is better the bees live on the contents of their stomachs for two days, than get wiped out by robbers. So, restrict the front entrance to the minimum. Then give it a day and see how the robbing situation is. If they are still getting robbed remove the feeder for two days. When you put the feeder back give them a small amount just before dusk. Do this daily, once robbing has ceased you can step up the feeding.
One of the biggest catch 22's that new beekeepers face in regard to feeding, is they see the hive is robbed and has no honey, so they feed even more, despite the robbers. Exactly the wrong thing to do it's like throwing petrol on a fire. While the bees just want the robbing to stop they have the beekeeper throwing more syrup in which encourages the robbers. The poor bees are in a hopeless situation and usually end up being wiped out.
44 years, been commercial, outfits up to 4000 hives, now 120 hives and 200 nucs as a hobby, selling bees. T (mostly).