We set our thermostat on 70 and by 12 noon it reads 80 degrees. The air that comes out of the vents is very low pressure, like there is a blockage. The maintenance crew has worked on it several times, but no improvement. The air stays on all day and night and only starts to shut off and on at around 4 am. It also freezes up a lot, outside and inside. What could the problems be?

Dirty air filter.
Dirty inside coil
Dirty outside coil.
Low refrigerant charge
High refrigerant charge
Maintenance men usually are not professional HVAC people but more of a jack of all trades. This could also be part of the problem.