If I understood your narration very well, I wouldn't be too warried about who the new person is behind the telegram account. I am more concerned about the deposit that has been made to you. Are you going to inform law enforcement agencies and give them the money so that they can carry out an investigation and where possible trace and return the money to the owner since the job was not done? Just block the new person and the problem is solved. Whenever the old person resurfaces, they can always reach via your telegram handle.