That could be part of a problem if it isn’t circulating.

Make sure all the vents are open and not blocked by something inside. Switch filters if you haven’t recently, and make sure they are the right kind for your unit. If you can get to your duct work, see if it is leaking anywhere as that will reduce the pressure at the vents.

If you have ceiling fans, turn them on to help out. If you aren’t already, close curtains to block direct sunlight (east side in the morning, west in the evening).

I would recommend having a different company check it out since they won’t be defensive about the prior work.