Radiator leak

Just had a coolant pressure check done and the mechanic said it needs the thermal housing unit replaced and a new hose. They did the work and I drove it home (4.1 miles). Pulled in the driveway and the car was smoking, no coolant and a trail of coolant behind me. There was coolant blown all over the engine compartment. I called to tell them and they sent a mechanic to my house. The filled up the coolant and without turning on the car it poured out of the radiator within two minutes it was out of coolant. The hole was so big we just watched it pouring out. They said it was not their fault and the hole just happened after I drove it the 4.1 miles home. Is that possible? I feel it would have been a pin hole first and not a large hole immediately. I also know they called around town looking for the attachment to run the test for a Mini so I feel like they over pressurized it. Could that have happened? It is too coincidental to me and they are taking zero responsibility. They will not even let me call the shops owner because they said they do not have his number. They want $542.00 for an after-market radiator and the labor to replace it.