Blown head gasket, block check

My car overheated on the way from work on Friday. I stopped the car when the warning chime came on and temperature gauge was pegged. Waited about 5 to 10 minutes and restarted. Temperature was normal but after a mile or so it did it again. Stopped and decided to call a tow truck. Once towed to the repair shop I let the tech know what was happening with the car. He told me that it could be multiple things and that they would do a block test on Saturday to see if there was any damage to the engine first as if there was the repair expense might be too high as it is a high mileage 8 year old car. He calls me Saturday and says that the water pump and thermostat housing needs replaced at a cost of just under $1,000.00. I bought the car new, it's the LTZ/RS and has been well kept. I told him to go ahead and do the work and he told me I could pick it up Monday. Monday morning I get a call from a different tech who tells me that the repairs were made but the car is still overheating and I need a new head gasket and if done the cost will be about $3,000.00. I asked about the block test that was supposed to alert to this before repairs were started and he told me that wasn't done as the water pump was so bad it just poured out water so badly the test could not be performed. When I went to the shop yesterday to pay the first tech I had dealt with said that the block had passed the test but the gasket failed after the repairs were done. I paid for the first repairs and told them to let me think about it. I am feeling a little like I have been deceived and am wondering if what the second tech said about not being able to perform the test due to the water pump is true. Is there a workaround for these situations? If the gasket was actually found to be sound as said by tech one, would it fail that soon after repairs. I feel that I am due a discount on the head gasket job as at this point it has to be done.