Can you provid3 pictures or plans?
Generally, the roads are the responsibility of the highways agency. Including the act of dropping curbs.
Unfortunately, I cannot comment on what the neighbours may have or have not done and what action the highways agency has taken against them, if any.
As it stands, from the information you have provided, I would suggest that it is prudent to wait until you have received a full response from the Highways Agency before commencing any further works. Failure to do so may result in you incurring charges from the Highways Agency.
I would suggest that you inform the Highways Agency that the surrounding neighbours have carried out similar works and if you are requested to return the area to its former state that they should be requested to do the same.
I hope this answers your question. If so, kindly rate the answer and provide feedback.
If you have any further questions, please do not hesitate to ask.
That seems like the corrwct course of action.
I hope this answers your questions. If so, kindly rate the answer and provide feedback.