Tvs Motor Company — in running condition gear auto change 4 to 3

Address:

382415

With reference to the above subject, when i have driving the my new bike tvs sport dura-life in some time accedantly change gear from 4th to 3rd gear its a very dengereous for life.
1. For above problem i have meet our service centre but they are not complate resove it.
Give your feedback me urgently
i awating for your reply