Do we have a malpractice suit?

In December, my husband got a speeding ticket in another county. We were going 94 in a 65. The ticket required a manadorty court appearance in January. We immediatley contacted a lawyer from that county who said he could get it "taken care of" for $315. The check was sent and was cashed by him, so we figured it WAS "taken care of". This week a state trooper showed up at my door while I was home with our kids, to arrest my husband. My husband was at work at the time and I explained the whole situation to the trooper, who then told me that when my husband got home that we needed to go turn him into the police, he had a warrant for his arrest. So when my husband came home, he called the lawyer who admitted he forgot to do what he had to do to fix this ticket and that he was sorry. He did immediately contact the D.A. and the state troopers and get the warrant revoked, and the next day got the ticket reduced but we still ended up with 4 insurance points. He actually told my husband that this happens to him about twice a year! Can we sue this lawyer for the $315 and what kind of lawyer do we need. We are in N.C.