Overheating

I recently had work done on my 1996 Lumina. I had the intake manifold gasket changed and a tune up. The car acted fine for the first day after spending $1300. It overheated. So i took it back to the shop. They said there was air in the system and they bleed it.still overheats. My brother changed the Thermostat and the Ect. Fan works and new relays. Still overheats. So last effort he changed the water pump. Still overheats. Also the heat is on blowing nothing but cold air. Any Ideas or should I junk it