Why doesn't my Air Conditioning work in my house?

Is literally been fixed like 3 times in three years and used to work when I first moved in, only had the house for about 6 years, the weird thing is it ******* works in the winter spring and fall yes sometimes we like AC in the winter but as soon as summer rolls around we get rammed in the *** with heat another thing is it works better in the morning than at night we have a shitty out dated thermostat that looks like a speedometer I don't need a repairman because we have called them and 2wks later its garbage again also i live in condominium complex with central air does this sound like ant kind of problem you heard of does it have a solution or should my conclusion be that my house was built over a Indian burial ground because im reading back on this now drowning in my own sweat thinking im crazy.