"The point, Banty, that we all have learned here is that we truly get
what we pay for. If we want cheap, that's perfectly fine as long as
we don't bitch about the consequences. If we want well done and
fabulous, we either have to pay good $$ or educate ourselves fully in
order to get that result. "

I don't see how cheap has anything to do with this situation. Price
didn't appear to be an issue when she chose the plumber to replace the
sink. I agree with the posters who now say it is the plumber's
responsibility to fix this correctly. He provided the sink. When he
removed the old one and determined that the new one had too small a rim
to cover the countertop properly, he should have stopped right there.
He could have taken the new sink back and very likely found other sinks
that have a slightly wider rim. Problem solved. Instead, he went
ahead and did a half assed job. And I think we've all seen people
charged all kinds of prices, both high and low for crap work.

If he hasn't damaged the sink, the best solution would appear to be for
him to return it and get the right one.