They swapped your springs with something else. Who knows with what. Maybe a 69/70 set? I've seen plenty of shops trying to cover crap like a cat like that. Springs don't ever get longer. Pull them off. Measure the relaxed height. Count the coils. Go from there. Step one is to no longer trust what they have said. A friend took an old truck to get some new tires. Came back with quite a few pieces missing. Funny how the mechanic had a similar truck. Hard to prove. You do the math. That's one reason why I do my own work.