Is Zerodha playing dirty tricks with Kuvera?

Zerodha launched its mutual fund product (coin app) very recently and here is what also happened.
Mutual fund player, Kuvera (now competitor) has noticed a sharp drop in its play store rating from 4.3 to 3.8 in 3 days.
Checkout Kuvera CTO, Mayank’s tweets.

Is this person your employee @zerodhaonline Hard to believe. But this is not one off example. pic.twitter.com/D544JBerzu

— Mayank Sharma (@mayanks) June 19, 2018

Coincidence you say? How can I be 3'rd time lucky? pic.twitter.com/GhAx8sIp89

— Mayank Sharma (@mayanks) June 19, 2018

Also, the same set of users rated @zerodhaonline coin app as 5 star around exactly the same time they rated our app 1 star.

— Mayank Sharma (@mayanks) June 19, 2018