Hello Melissa,

Sorry about your robbing issues.  There are a lot of techniques people use to avoid robbing.  I've not had any luck with them after the robbing has started.  Once the robbers find a weak colony with any stores, they are pretty relentless bees aren't smart, but they aren't stupid either.  (it's a lot easier and more efficient to steal honey from a weak colony than it is to collect nectar from forage plants)

What has worked after robbing has been established, is to move the hive to another location, at least a mile or two away and bulk them up with bees if possible, and perhaps a robbing screen to avoid it getting started.

In the future, it's much easier to avoid, than to fix.  Keep the colony strong and healthy.  during a dearth, keep your inspection times to a minimum, and even use an inspection cover (canvas sheet with a slot to cover the top of the hive, leaving an opening to pull out frames one at a time.  Clean up or avoid honey and wax spills.

Best of luck with the colony.