You need to train the dog!
I love my dog so much but it constantly did the things that irked me most. It would chew on things that it shouldn’t or jump up and down out of the blue. Whenever I put on the leash, it would pull on it. Whenever it was out of the house, it would continue digging on the ground - I wish I could tell what it was looking for down there. All the things it did left me feeling depressed as if I failed it monumentally.
But since I discovered Brain Training for Dogs and applied the system offered, it now behaves the way a beautiful dog I always expect of.
I'm in the same predicament. I have a little Pomeranian mix that is very possessive of mommy ever since his big brother (German Shepard/husky mix) passed away two months ago. Our neighbor's dog is a beautiful malamute who digs his way over into our yard. Now he has figured out the doggy door and just helps himself inside, much to the dismay of my little dog. I work from home and when he comes inside, my dog will defend his territory. I am continually taking myself off the phones so I can deal with any dog arguments (My dog is mostly all talk but has gone full on psycho a time or two). I have been dismantling my raised flower beds and filling holes with the concrete blocks but to no avail. The neighbors are hard to reach and we've mentioned it before but they have taken no action on their side to prevent the issue. I suspect their dog (which is a high energy/intelligent breed) is lonely, bored and probably looking to play with our dog that passed away. I don't want anything to hurt him and thus far, my position has been that it is better he break into my yard than break out all together and get lost, stolen or hit by a car. We're going to approach the neighbors again and offer to help pay for any fencing needs and to help come up with some solutions. (I used to work for/with a pet rescue organization so we have advice in spades!) I really think they need to invest in either a doggy day care or a dog walker/sitter. Malamutes, huskies and German shepherds (like my old one) are know for anxiety issues and being high energy/intelligent breeds that need A LOT of interaction/attention.