Hero Motocorp — very poor service

Address:

A 72 Chawra colony housing complex, 201006

Dear concern,
I get the service of bike done through your service centre and changed the chain set and indicator but my problem is still the same again the chain set broke.
If some kind of mishappening accured, then who will be responsible for it.
Due to such carelessness people are getting fool.
I have already paid 2250 for this after that also the problem remains the same and when i speak to your service centre they misbehave.
Kindly provide some instant solution to this problem else i will take some strict action.