Problem Neighbours - Update

So last night was definitely interesting.
After contemplation and discussion, my mother (home owner), called the neighbour to try and talk about the situation and see if they could help resolve answer our questions. Well, this did not go over well at all. The 83-year old neighbour proceeded to scream and yell profanities at my mother prior to hanging up the phone. In addition, she commented that all we ever do is complain, and they didn't complain to us about the hole in our front lawn last year.
**SIDEBAR** The hole in the front lawn was dug by the city in response to the neighbour's complaints about water pressure, and we had no say in the matter because the waterline ran up our lawn. For months my father called the city, the contractor who was supposed to repair the lawn, local MPs, and the response was always "it will be fixed by the end of the week". NOW, the neighbour's son claims to have been the one who called the city and got it sorted out for us **anyone else notice that his comment about him calling the city means that they must have known that it wasn't our responsibility to repair the lawn?**
Perhaps we wouldn't need to complain to the neighbours if they were respectful of our property. In the past, we have complained...about the neighbours parking on our lawn, throwing their cigarette butts in my gardens (including cigarette packages, wrappers, etc.), about finding 12 empty cans of coke thrown into the backyard over their fence, about finding a large lump of ice salt in the backyard beside their fence that has caused a bald patch in the lawn, and about the grandson bouncing a ball off the side of my house. I try not to take it personally, but I find it hard.
Back to last evening, after the phone call where my mother was verbally abused, the neighbour's daughter came over yelling at us for upsetting her mother. After a 15 minute discussion about our simple, reasonable requests that cause no hardship on them, but prevent hardship for us, she seemed to calm down. I advised her that if she contacts her contracted snow removers about the problem, and if they ever decide that midnight is the optimal time for snow blowing, I will phone the police to file a complaint. I do not wish for there to be bad blood, I don't want to have to call the police, but if I have to resort to that measure, I will.
After the conversation with the daughter, my boyfriend went to take the dog out and the neighbour's son decided he wanted to start bitching at us as well. I wasn't privy to all of the details, but understand he was rather jerky about the situation (which I really believe was blown out of proportion due to the reaction of his mother). We have been warned not to speak with his mother ever again. He made the previously discussed comments about the hole in our lawn, which is such a stupid and irrational argument on their part, so was not discussed further by us. And the only saving grace was a comment that he made, "Don't worry, when she dies, we're out of here!". That was a surprise comment, kind of startling, but at the same time is a light at the end of this dark tunnel.
I still sleep uneasily as I fear retaliation for our requests of consideration and respect. Only now, I'm fully prepared to contact the authorities if they harass us in any manner. I have been nice, tried to give them the benefit of rectifying the situation without intervention, but so help me if they pull any crap, I'm calling them on it. And I'm pretty sure that I would have full support of the neighbourhood if needed.

Fingers crossed,
C.R.