Ball joint problems?

the large bolt ball joint will not fit into the spindle unless its reamed out. sounds like the upper arm may be stretched out.. a replacement may be in order. or maybe you have large bolt and the wrong ball joint was in the box? were the two ball joints the same? the shop doesn't sound like they know what they are doing. if they have been doing these cars since new i would think they would know how to fix the issue. any idea what they put a shim in??