Hi I'm new to this site an need a little help my question is since quite some time my ac I been setting I up at 75 when is really a hot day instead of being inside at 75 is at 83 but at night time it goes down to 75 last year we put freeon but the problem still exist what could that be an thanks in advance

If you added refrigerant, and it didn't need it, you just made the issue worse. Time to call in a professional tech and have them evaluate the system. If adding refrigerant made the system work for a while, that means you have a leak in the system, and that needs to be found, fixed, and system recharged. Lots of things that could be happening here. Please let us know what the tech finds.