SaunavDas Hey man, don’t act ungrateful. The developer never asked you to buy the app, it was your sole decision to do it. He does have the V1 available for free on GitHub, if you do not want to buy the app use that.
At most, what you can do is “Request” the developer to add/improve something (it is still up to him if he does that or not.)
It is better to just get a refund if you don’t like the app, rather than asking the developer to make it “Perfect!”