What part does it need to repair it? It's a standard SAE pattern starter, unless all they are is a stocking reseller for overseas reman parts, whoever looked at it should be able to list five starters in a dozen configurations off the top of his head that would bolt right in. More if he wants to get out the catalogs.
IMHO if they didn't recognize a standard drive and/or offer interchange information when it was condemned for whatever part it was, don't count on that part being unobtainable or difficult to change. Your starter just wasn't on the quick reference chart on the back wall.