If they tried to replace the pump without moving the radiator, which means draining and disconnecting it, they may have nicked the core with the fan clutch assembly....I barely touched mine and messed up some of the fins and had to straiten them when removing my fan and clutch assembly to install the e-fans, its very easy to damage the radiator.
Ask to see the radiator, if the damage is in the middle and not a leaking end-cap, you can almost bet either the fan was wobbling due to the bad pump and hit the radiator (which should be covered) OR the tech damaged it during pump replacement.
Ask to see the radiator, if the damage is in the middle and not a leaking end-cap, you can almost bet either the fan was wobbling due to the bad pump and hit the radiator (which should be covered) OR the tech damaged it during pump replacement.