Too small ---- How?

If the new frame is identical to the old frame than the same BB cranks and FD should all wok together properly.

However, possibly there were some subtle changes between the two editions.

More likely however, is something was pooched when the BB was installed. Depending on the type, a spacer could have been omited o misplaced, the spindle reversed, or whatever, causing a change in the chainline or lack of clearance at the chainstay.

If the issue was chainstay clearance, that's a bb installation problem, if the inner ring clears the chainstay, then it's a mechanic problem because I don't know of any way the inner ring could be too far inboard for the FD.

Ask them to clarify the issue, so you can deal with accordingly.