unfriendly neighbours, harrassing

I live in Ontario, Canada. My house was built in the 1920's. My parents lived in it and I was brought up in it. I was left the house when they passed away. I am 55 rs. old. It has always been a friendly little block (4 houses) till the last 3 years when new neighbours moved in next door, which is about 5 feet east of us. First, they built a fence ( never told us), from the back of their house to the rear of their property 1 foot onto their property line. The told us we would have no say about it and can not go within 1 foot of it. This is hard to do cause we do have to mow our lawn. My husband went in between the houses to cut weeds from around our air condition unit and proceeded to cut the rest of the 5 x 20 area. The neighbour proceeded to come out and informed him he was cutting their lawn (which did need cutting). I mentioned the unit needed trimming and he just thought he might as well do the rest. So after she informed us she didn't like us my husband put things away and left. Everyone around here helps each other except them. Also, our front stoop encroaches about 1 foot onto their property which has been there since I was a child. Now they have put up a structure and fastened it to our stair rail and stoop so we can't get through to the side of our house without going around to the back and walk between the houses, which they do not want us to do. We also, all summer, cut between their survey posts and their fence because they would never do it. I did inform them of that and was told not to cut it. We do have to see it and it looks awful. Is their anything we can do? They seem to be nit picking about everything we do.