Huge and continuous lag in an area because of fireworks

Hi, Me and my friends are very worried about our server. Fireworks launched with an glorious redstone-based system which fired 48 rockets together condemned an entire area of our world (a beautiful venetian city to be more specific - more than a week of work), which is stuck in a continuous huge lag (nearly freeze) preventing from doing anything. The rest of the world is not affected.
Disconnect and reconnect does not help.
Restart the server does not help.
Wait staying connected does not help.
Can Mojang help please, or is our city lost for ever?