The 3 Wild Plums.

I have 3 Wild Plums in my garden. I moved in 25 years ago and they were here already. Now I have trouble with my neighbors because the garden wall is under pressure. The trees are close to the wall but not touching. I am digging down to the foundation to see if these trees are the sole culprets. The neighbors insist I remove them, but the thought is breaking my heart. If I can reduce the drip line circle and top the trees, will it encourage an agredsive spread of the roots or limit the spread? To what extent will one-sided 'pruning' destabilize these trees. I guess they are to close to the wall. But surely, there must be some affordable way to save the trees and secure the wall!? Any advice will be appreciated. Solette