Neighbour's Trees are damaging my property

Greetings! My neighbour has a pair of wild ashoka tree abutting our compound wall. On the compound wall lies our main electric board and besides, there lies an underground water storage tank. The thud of the trees have already caused numerous cracks in our wall and the roots have penetratred into the water tank. I fear that in future this might get even more deleterious and might cause a huge power shut down for our house. We have tried talking to our neighbours, humbly explaining the matter but they always seem to equivocate the conversation and delay the cutting. We even asked the municipal corporation and they said that they can only grant them the permission and not interfere in cutting down action. Moreover, the tree branches have never been trimmed off and are scattered through out. It blocks light and there also is a huge issue regarding shedding of leafs along our side. The compound wall is built by us and it lies on our land which they also have been using to mount lamps and bamboo blockades which further restrict the light. I've tried so much but it seems we have to go down the legal road since they won't cooperate. Could you please guide me with the steps I should be taking in the future to mitigate my damages and get those trees chopped off? Thank you