I think my neighbor's dog has serious aggression issues and I am not sure what to do.?

Wheneve i am outside the dog, which is a large mastiff, charges at the fence at full speed growling and making really scary noises (similar to a wild animal). It then jumps onto the fence (which is Not very sturdy) and continues to lunge and growl at me as it attempts to break through or dig under the fence. I have never seen a dog act this way before and i am afraid it is going to get through the fence and hurt me. Is this normal dog behavior? It broke through the fence once before and nearly got my dog and i before we ran into the house. I have told the neighbor this isnt acceptable, but nothing has changed. What should I do?