The company should have given you a report of what chemicals - organic or manufactured- were sprayed on the lawn. You can share a photo of that if you would like or let us know what the chemicals are just so we have a better idea of what was applied and is clearly affecting the plants. 

Either way there isn't much you can do to fix the problem but wait to the plants to recover, hopefully. You can prune off any of the burned foliage that looks like it will not push out new leaf growth. If it was a systemic application meaning the plants will take up the chemicals through the roots, then you will just have to wait to see if it affects the plants further. In times of dry weather you can water at the base of the plants to help leach out any chemicals in the root zone. 

In the future since it sounds like this has happened twice now, if the company can let you know when they are coming you could try to shield the plants with pieces of cardboard or a tarp so the foliage doesn't come in contact with the chemicals, if they can't seem to not spray the leaves.  Maybe you could also ask them to leave more of a gap between the lawn and plant spray. If it is a windy day though (which there are wind limits that they can apply with) then it may still bother the plants. 

Feel free to send back a photo of the report so we can review what was used and see if there is any other guidance we can suggest. 

Emily