"You're not the first one who's had trouble with money," said Mr. Roberts, scrutinizing Mr. Weasley closely. "I had two try and pay me with great gold coins the size of hubcaps ten minutes ago."
I think "I had two try" here means Mr. Roberts had encountered this kind of situation two times. (Is my understanding correct?) I don't quite understand why the singular form of 'try' is being used, instead of the plural form "tries", given the word 'try' is actually an accountable noun. Is it a dialectal usage?