Neighbor putting snow on my house?

I would record as much as possible if you are catching them in the act. Explain to them what it is doing to your house and what the cost's are (try to record that also) and that you need them to stop, please. After that you need to notify the law. After the law talks to them and if they keep doing this then you ned to take them to small claims court and sue them for your damages. Sometimes ppl don't listen unless you hit there wallet. I lived in Michigan for years and always directed our now to the curb.