Who called from 8137230623

Call came in about 11:30 a.m. EDT from Florida. No other information, besides the calling #, was provided in the voice mail which said voice mail said, simply, "Good-bye".

When I answer, there is no one there.   When I call back, I get a fast busy.
Who are these people, and what  do they want?

moron don't even speak english....best way to handle is to blow shrill whistle into ears....;maybe after
their head clears they'll take me off their scamming calls..;..;