2018 Jeep Wrangler Unlimited JK

3.6L V6 24V VVT

Took the Jeep into the local shop to have a check engine light looked into. Came back needing a new thermostat but was told the vehicle was fine to drive. Drove over Thanksgiving and on the way home Jeep starts to overheat. I pull over and have Jeep towed to service shop. Now instead of a $400 bill I’m looking at a $2,000+ bill with no assurance that something isn’t further wrong with the engine due to overheating. Shop is saying the P0128 code indicates that the thermostat was stuck open thus the “fine to drive” line. Is it possible that it closed or something else with the thermostat suddenly caused damage to my Radiator and the leak thus the additional repairs and expenses? Shop is saying it’s a “coincidence”.