Our next door neighbour keeps making untrue allegations against us?

and has come round using threatening behaviour towards my husband, its all rubbish but he obviously doesn't like us. I want to get a solicitor to send him a letter to point our that he is actually haring us, and we want him to stop, but don't know how much this would cost. The man has anger issues and we just want for him to shut up, go away and leave us to lead a quiet life.