He probably got the beginnings of some excellent representation, but my suspicion is that they "walked" because he racked up an unpaid $2,000,000.00 bill with them.
I don't believe for a second that crooked Charlie paid anyone a plugged nickel to defend him.
Another article here:
Rangel ethics case in hands of jury of lawmakers
There's a few interesting paragraphs in it:
Vermont Democratic Rep. Peter Welch said that no law firm should be "taking the money ... and kicking their client by the side of the road."
Rangel's former law firm of Zuckerman Spaeder disputed his assertion that he was abandoned.
"This law firm did not seek to terminate the relationship and explored every alternative to remain as his counsel consistent with House ethics rules prohibiting members from accepting pro bono legal services," the firm said. "Out of respect for Congressman Rangel and the House ethics committee, we will not comment further at this time."